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The mouse Rbpj gene (UniProt accession P31266) encodes the Recombining binding protein suppressor of hairless, also known as RBP-Jκ, RBP-J, or CSL (an acronym for CBF1/Suppressor of Hairless/LAG-1) (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjl pages 1-2). The protein belongs to the Su(H) family and contains characteristic domains including a beta-trefoil DNA-binding domain (IPR015350) and Ig-like fold structures (IPR013783), consistent with the functional annotations in current literature (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjl pages 8-12).
Rbpj encodes a sequence-specific DNA-binding transcription factor that serves as the central nuclear mediator of canonical Notch signaling in mammals (giaimo2021transcriptionfactorrbpj pages 3-5, kou2024rbpjregulateshomeostasis pages 1-2, hall2022thestructurebinding pages 1-2). Importantly, RBPJ is not an enzyme with catalytic activity; rather, it functions as a DNA-bound molecular scaffold whose primary "substrate" is the regulatory DNA at Notch-responsive genes (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8).
RBPJ recognizes canonical CSL response elements centered on the consensus sequence 5′-GTGGGAA-3′, with the extended motif 5′-CGTGGGAA-3′ frequently cited as a representative high-affinity binding site (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjla pages 12-14). DNA binding is mediated primarily by the N-terminal and beta-trefoil domains, with the conserved arginine residue Arg218 playing a critical role—mutation of this residue (R218H) abolishes canonical DNA binding and dramatically reduces nuclear residence time from approximately 910 seconds to 194 seconds (pan2021transcriptionfactorrbpjla pages 12-14, pan2021transcriptionfactorrbpjl pages 12-14).
RBPJ functions as a context-dependent molecular switch that converts Notch signaling inputs into transcriptional outputs (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8). In the absence of Notch signaling, RBPJ remains constitutively bound to target-gene regulatory elements and actively represses transcription by recruiting corepressor complexes (giaimo2021transcriptionfactorrbpj pages 5-8, giaimo2021transcriptionfactorrbpj pages 3-5). Following Notch receptor activation and proteolytic release of the Notch intracellular domain (NICD), NICD enters the nucleus and binds RBPJ, converting the DNA-bound complex from a transcriptional repressor into an activator (hall2022thestructurebinding pages 1-2, giaimo2021transcriptionfactorrbpj pages 3-5, sprinzak2021biophysicsofnotch pages 13-14).
RBPJ contains three principal structural domains: an N-terminal domain (NTD) or Rel-homology domain, a central beta-trefoil domain (BTD), and a C-terminal domain (CTD) or Rel-homology domain (sprinzak2021biophysicsofnotch pages 13-14, pan2021transcriptionfactorrbpjl pages 8-12, hall2022thestructurebinding pages 1-2). A single extended beta-strand connects all three domains, organizing them into a compact overall fold (hall2022thestructurebinding pages 1-2). The N-terminal and beta-trefoil domains provide the principal DNA-recognition surfaces, while the beta-trefoil and C-terminal domains create distinct interfaces for regulatory protein interactions (sprinzak2021biophysicsofnotch pages 13-14, pan2021transcriptionfactorrbpjl pages 8-12).
When Notch signaling is inactive, RBPJ associates with multiple corepressor proteins that establish transcriptionally repressive chromatin states (giaimo2021transcriptionfactorrbpj pages 5-8). Key corepressors include:
SHARP/SPEN: The central corepressor that uses a bipartite interaction mode, binding both the beta-trefoil and N-terminal domains of RBPJ (sprinzak2021biophysicsofnotch pages 13-14, hall2022thestructurebinding pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2). SHARP recruits additional repressive machinery including NCoR–HDAC complexes and ETO/MTG family corepressors (sachan2023notchsignallingmultifaceted pages 5-6, giaimo2021transcriptionfactorrbpj pages 5-8).
L3MBTL3: Binds exclusively to the beta-trefoil domain and recruits the repressive histone demethylase KDM1A/LSD1 (hall2022thestructurebinding pages 1-2, giaimo2021transcriptionfactorrbpj pages 8-10). Crystal structure analysis of the RBPJ–L3MBTL3–DNA complex revealed that L3MBTL3 occupies a narrow hydrophobic groove on the beta-trefoil domain surface (hall2022thestructurebinding pages 6-7).
FHL1/KyoT2: Interacts with the beta-trefoil domain hydrophobic groove, competing with NICD for the same binding surface (sprinzak2021biophysicsofnotch pages 13-14, giaimo2021transcriptionfactorrbpj pages 8-10).
Additional repressive activities recruited through these corepressors include the histone demethylases KDM5A and KDM1A, which help establish and maintain repressive chromatin marks at RBPJ-bound enhancers (giaimo2021transcriptionfactorrbpj pages 8-10).
Following Notch activation, the released NICD enters the nucleus and forms a ternary transcriptional activation complex with RBPJ and Mastermind-like (MAML) proteins (hall2022thestructurebinding pages 1-2, sprinzak2021biophysicsofnotch pages 13-14). The RAM (RBPJ-associated molecule) region of NICD binds with sub-nanomolar affinity to the hydrophobic groove in the beta-trefoil domain through its conserved WFP (tryptophan-phenylalanine-proline) motif, occupying the same surface used by corepressors (sprinzak2021biophysicsofnotch pages 13-14). The ankyrin-repeat domain of NICD then contacts the Rel-homology domains of RBPJ, while MAML bridges these components by forming a composite interface with both NICD and RBPJ (sprinzak2021biophysicsofnotch pages 13-14, hall2022thestructurebinding pages 1-2).
The activated RBPJ–NICD–MAML complex recruits transcriptional coactivators and chromatin-modifying enzymes, including:
- p300/CBP (KAT3B), PCAF (KAT2B), and GCN5 (KAT2A) lysine acetyltransferases (giaimo2021transcriptionfactorrbpj pages 3-5)
- EP400/TIP60 chromatin-remodeling complexes (giaimo2021transcriptionfactorrbpj pages 8-10)
- Mediator complex components (hall2022thestructurebinding pages 1-2)
These coactivators promote histone acetylation, enhancer activation, and target-gene transcription (giaimo2021transcriptionfactorrbpj pages 8-10, giaimo2021transcriptionfactorrbpj pages 3-5).
RBPJ carries out its primary transcriptional regulatory function in the nucleus (pan2021transcriptionfactorrbpjla pages 12-14, pan2021transcriptionfactorrbpjl pages 12-14, kou2024rbpjregulateshomeostasis pages 1-2). Live-cell single-molecule tracking experiments demonstrated that wild-type RBPJ exhibits nuclear binding events with a longest residence time of approximately 910 seconds, consistent with stable DNA occupancy (pan2021transcriptionfactorrbpjla pages 12-14, pan2021transcriptionfactorrbpjl pages 12-14). This long nuclear residence is dependent on DNA binding, as the R218H mutation that disrupts DNA recognition reduces the longest binding time to 194 seconds (pan2021transcriptionfactorrbpjl pages 12-14).
However, RBPJ localization is not strictly nuclear; the protein undergoes regulated nucleo-cytoplasmic shuttling dependent on cofactor interactions (wolf2021nucleocytoplasmicshuttlingof pages 2-4, wolf2021nucleocytoplasmicshuttlingof pages 1-2). Studies using murine RBPJ in a Drosophila genetic model demonstrated that RBPJ distribution follows that of the Hairless protein: variants defective in nuclear import retain RBPJ in the cytoplasm, while variants defective in nuclear export cause RBPJ accumulation in the nucleus (wolf2021nucleocytoplasmicshuttlingof pages 2-4, wolf2021nucleocytoplasmicshuttlingof pages 1-2). In mammalian cells, the tubulin-binding protein RITA1 can promote nuclear export of RBPJ (sprinzak2021biophysicsofnotch pages 13-14). This dynamic regulation of nuclear availability may provide an additional layer of Notch pathway control (wolf2021nucleocytoplasmicshuttlingof pages 2-4, wolf2021nucleocytoplasmicshuttlingof pages 1-2).
RBPJ regulates a well-defined set of canonical Notch target genes that control cell fate, proliferation, and differentiation (pan2021transcriptionfactorrbpjla pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2, giaimo2021transcriptionfactorrbpj pages 1-3). Key target genes include:
Hes and Hey families: Basic helix-loop-helix (bHLH) transcription factors that are among the most direct and well-characterized Notch targets (pan2021transcriptionfactorrbpjla pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2, giaimo2021transcriptionfactorrbpj pages 1-3). HES1 and related family members function as transcriptional repressors that mediate many downstream Notch effects.
c-Myc: A pivotal transcription factor controlling proliferation and identified as a canonical RBPJ-regulated Notch target (pan2021transcriptionfactorrbpjla pages 1-2, giaimo2021transcriptionfactorrbpj pages 1-3).
Dtx1/Deltex: Functions as both a Notch target and a feedback regulator of the pathway (pan2021transcriptionfactorrbpjla pages 1-2, giaimo2021transcriptionfactorrbpj pages 10-12, pan2021transcriptionfactorrbpjl pages 1-2).
Nrarp: Another feedback regulator identified as a Notch-responsive gene (pan2021transcriptionfactorrbpjla pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2).
RBPJ binding sites can be classified into "static" sites, where RBPJ occupancy is largely Notch-independent, and "dynamic" sites, where RBPJ recruitment increases following NICD binding (giaimo2021transcriptionfactorrbpj pages 10-12). This distinction reflects the dual role of RBPJ in both maintaining genes in a poised repressed state and in mediating their activation upon signaling.
RBPJ-mediated Notch signaling is essential for mouse embryonic development, with complete germline disruption causing early embryonic lethality (solano2025defectivenotch1signaling pages 4-5, solano2025amousemodel pages 43-49). Through its role as the terminal nuclear effector of canonical Notch signaling, RBPJ participates in morphogenesis of multiple organ systems, including the heart, vasculature, hematopoietic system, nervous system, and somite-derived structures (solano2025defectivenotch1signaling pages 1-2).
Recent studies using Adams-Oliver syndrome (AOS)-associated Rbpj variants have revealed crucial roles in vascular development (solano2025defectivenotch1signaling pages 1-2, solano2025amousemodel pages 6-10, solano2025defectivenotch1signaling pages 5-6). The AOS-associated E89G variant, which impairs DNA binding while retaining cofactor binding, causes severe embryonic cardiovascular defects when combined with Notch1 haploinsufficiency (solano2025defectivenotch1signaling pages 5-6, solano2025defectivenotch1signaling pages 1-2). Importantly, conditional genetic experiments demonstrated that endothelial expression of the Rbpj E89G allele is both necessary and sufficient to cause lethality and cardiovascular abnormalities, establishing that reduced Notch1–RBPJ signaling in the vasculature is a key driver of pathogenesis (solano2025defectivenotch1signaling pages 1-2, solano2025amousemodel pages 6-10).
Conditional deletion of Rbpj in Lyz2-expressing myeloid cells revealed cell-intrinsic roles in regulating circulating monocyte populations (kou2024rbpjregulateshomeostasis pages 1-2). RBPJ-deficient mice exhibit marked accumulation of Ly6Clo (non-classical/patrolling) monocytes that abnormally express high levels of CCR2, along with expansion of Ly6Clo monocytes and CD16.2+ interstitial macrophages in the lung (kou2024rbpjregulateshomeostasis pages 1-2). Genetic deletion of Ccr2 corrected these phenotypes, indicating that RBPJ normally constrains this population at least partly through regulation of CCR2 expression (kou2024rbpjregulateshomeostasis pages 1-2). The phenotype does not result from altered monocyte apoptosis, proliferation, or Ly6Chi-to-Ly6Clo conversion kinetics (kou2024rbpjregulateshomeostasis pages 4-5).
Conditional deletion of Rbpj in embryonic ectoderm (beginning around E8.5) produces severe craniofacial, skin, and hair-follicle defects (zhao2026notchsignalingin pages 8-11). Mutant mice display complete secondary palate clefts, extensive oral epithelial adhesions and fusions, disrupted periderm development, markedly thinned epidermis, and malformed vibrissa follicles with ectopic mineralization (zhao2026notchsignalingin pages 8-11). These findings establish that canonical RBPJ-dependent Notch signaling promotes proper periderm and epidermal cell fate while preventing inappropriate adhesion and mineralization programs during craniofacial development (zhao2026notchsignalingin pages 8-11).
Beyond specific tissue contexts, RBPJ-mediated Notch signaling broadly controls developmental decisions during both embryonic and postnatal life, including cellular differentiation across multiple organ systems, stem-cell maintenance, and apoptosis regulation (pan2021transcriptionfactorrbpjla pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2). The pathway is dosage-sensitive, with insufficient or excessive Notch-RBPJ activity disrupting normal tissue regulation and potentially promoting oncogenesis (pan2021transcriptionfactorrbpjla pages 1-2).
A summary of key mouse phenotypes is provided in the table below, illustrating the range of developmental and tissue-specific functions:
| Tissue/developmental context | Rbpj perturbation | Observed mouse phenotype | Mechanistic interpretation | Evidence |
|---|---|---|---|---|
| Whole embryo | Germline disruption/null allele | Early embryonic lethality with severe growth and developmental defects, establishing that Rbpj is essential for embryogenesis. | Loss of the principal nuclear effector of canonical Notch signaling prevents normal developmental transcriptional programs. | (solano2025defectivenotch1signaling pages 4-5, solano2025amousemodel pages 43-49) |
| Vascular endothelium and cardiovascular development | Endothelial expression of the Adams–Oliver syndrome-associated E89G allele | Increased embryonic lethality and cardiovascular abnormalities; endothelial expression was both necessary and sufficient for the major disease phenotypes. | E89G impairs DNA binding while retaining cofactor binding, supporting dominant-negative cofactor sequestration and reduced endothelial Notch1 output rather than simple haploinsufficiency. | (solano2025defectivenotch1signaling pages 1-2, solano2025defectivenotch1signaling pages 5-6) |
| Notch1-sensitized embryo | Rbpj E89G/+ combined with Notch1 heterozygosity | Severe under-representation, embryonic lethality, failure to thrive, cardiovascular defects, and occasional scalp or skin abnormalities. Equivalent compound heterozygous null alleles were substantially better tolerated. | Demonstrates a strong, allele-specific genetic interaction with Notch1 and supports dominant-negative activity of E89G. | (solano2025amousemodel pages 6-10, solano2025defectivenotch1signaling pages 5-6, solano2025defectivenotch1signaling pages 1-2) |
| Whole embryo—severe disease-associated allele | Homozygous Rbpj E89G | Embryos were markedly smaller and displayed hemorrhage, pallor, pericardial edema, incomplete axial rotation, and embryonic lethality. | Severe impairment of RBPJ–DNA binding disrupts developmental Notch transcription, although the phenotype is somewhat less severe than complete Rbpj loss. | (solano2025defectivenotch1signaling pages 5-6, solano2025defectivenotch1signaling pages 4-5, solano2025amousemodel pages 10-14) |
| Whole animal—mild disease-associated allele | Homozygous Rbpj S358R | Mice were generally viable without major gross abnormalities; homozygotes were initially smaller but achieved normal size by about five weeks. | S358R behaves as a weak hypomorphic allele whose residual activity is sufficient in an otherwise unsensitized background. | (solano2025defectivenotch1signaling pages 5-6, solano2025amousemodel pages 10-14) |
| Whole animal—reduced Rbpj dosage | Rbpj S358R/null | Significantly reduced viability and marked growth impairment among survivors. | Pairing the weak S358R allele with a null allele exposes its partial loss of function. | (solano2025defectivenotch1signaling pages 4-5, solano2025amousemodel pages 10-14) |
| Myeloid lineage | Conditional deletion in Lyz2-expressing cells | Accumulation of circulating Ly6CloCCR2hi monocytes and expansion of Ly6Clo monocytes and CD16.2-positive interstitial macrophages in lung; additional Ccr2 deletion genetically corrected the phenotype. | RBPJ cell-autonomously constrains nonclassical-monocyte homeostasis and tissue distribution, at least partly through CCR2 regulation. | (kou2024rbpjregulateshomeostasis pages 1-2) |
| Myeloid lineage—cell kinetics | Conditional deletion in Lyz2-expressing cells | No major change in monocyte apoptosis, proliferation, labeling kinetics, or Ly6Chi-to-Ly6Clo conversion under the tested conditions. | The accumulation phenotype is unlikely to result simply from increased proliferation, reduced death, or accelerated subset conversion. | (kou2024rbpjregulateshomeostasis pages 4-5) |
| Embryonic ectoderm | Conditional ectodermal Rbpj deletion beginning around E8.5 | Neonatal death, complete secondary-palate cleft, extensive oral epithelial adhesions, disrupted periderm, thin epidermis, malformed cyst-like vibrissa follicles, absent visible whiskers, and ectopic mineralization at vibrissa sites. | Canonical RBPJ-dependent Notch signaling promotes periderm and epidermal cell fate while preventing inappropriate adhesion and mineralization programs. | (zhao2026notchsignalingin pages 8-11) |
Table: Mouse genetic evidence shows that Rbpj is essential for embryogenesis and has tissue-specific functions in vascular, myeloid, and ectodermal biology. Disease-associated missense alleles can behave as hypomorphic or dominant-negative variants rather than simple nulls.
These genetic studies reveal an allelic series: complete Rbpj loss causes early embryonic lethality, weak hypomorphic alleles (S358R) produce mild growth effects, while disease-associated alleles with impaired DNA binding (E89G) can act as dominant-negative variants that sequester cofactors and cause severe phenotypes when Notch signaling is further compromised (solano2025amousemodel pages 6-10, solano2025defectivenotch1signaling pages 5-6, solano2025defectivenotch1signaling pages 1-2).
Multiple crystal structures have been solved that elucidate RBPJ function:
- RBPJ bound to DNA, showing the molecular basis of sequence-specific recognition (pan2021transcriptionfactorrbpjl pages 8-12, hall2022thestructurebinding pages 1-2)
- RBPJ–L3MBTL3–DNA ternary complex (2.06 Å resolution), revealing the corepressor interaction interface (hall2022thestructurebinding pages 6-7)
- RBPJ–NICD–MAML–DNA quaternary complex, demonstrating the architecture of the activated Notch transcription complex (hall2022thestructurebinding pages 1-2)
These structures confirm that DNA binding and cofactor recruitment involve functionally separable surfaces, with the beta-trefoil domain serving as a critical hub for competitive cofactor binding (sprinzak2021biophysicsofnotch pages 13-14, hall2022thestructurebinding pages 1-2, hall2022thestructurebinding pages 6-7, hall2022thestructurebinding pages 11-12).
Biochemical studies using electrophoretic mobility shift assays (EMSA), isothermal titration calorimetry (ITC), and quantitative binding assays have characterized:
- DNA-binding affinities and the effects of AOS-associated mutations (solano2025amousemodel pages 6-10, solano2025amousemodel pages 43-49)
- NICD RAM domain binding to the RBPJ beta-trefoil domain with sub-nanomolar affinity (sprinzak2021biophysicsofnotch pages 13-14)
- The bipartite high-avidity interaction between SHARP and RBPJ (hall2022thestructurebinding pages 11-12)
- Single-molecule dynamics and nuclear residence times in living cells (pan2021transcriptionfactorrbpjla pages 12-14, pan2021transcriptionfactorrbpjl pages 12-14)
Recent work using single-molecule tracking in live cells revealed that RBPJ exhibits kinetic rather than thermodynamic DNA-binding stability, with target-site search times longer than residence times, indicating that effective in vivo binding depends on association kinetics as well as dissociation rates (solano2025amousemodel pages 43-49).
| Property | Mouse RBPJ summary | Functional significance | Evidence |
|---|---|---|---|
| Protein identity | RBPJ, also called RBP-Jκ or CSL, is the mammalian Su(H)-family DNA-binding effector of canonical Notch signaling. This identity matches mouse Rbpj rather than the pancreas-enriched paralog Rbpjl. | Confirms the target as mouse RBPJ, UniProt P31266. | (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjl pages 1-2) |
| Primary molecular function | Sequence-specific DNA-binding transcriptional regulator and protein-interaction scaffold. It is not an enzyme and catalyzes no chemical reaction. | Switches Notch target loci between transcriptional repression and activation according to the cofactors assembled on RBPJ. | (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8, hall2022thestructurebinding pages 1-2) |
| DNA-binding specificity | Recognizes canonical CSL response elements centered on 5′-GTGGGAA-3′; 5′-CGTGGGAA-3′ is a representative extended motif. Its functional substrate is regulatory DNA rather than a small molecule. | Positions RBPJ at Notch-responsive promoters and enhancers. | (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjla pages 12-14) |
| Domain architecture | Contains an N-terminal domain or Rel-homology domain, a central β-trefoil domain, and a C-terminal domain or Rel-homology domain. A β-strand extending across the domains helps organize the compact fold. | Integrates DNA recognition with recruitment of activating or repressive partners. | (sprinzak2021biophysicsofnotch pages 13-14, hall2022thestructurebinding pages 1-2) |
| DNA-binding surfaces | The N-terminal and β-trefoil domains form the principal DNA-recognition surfaces. Conserved Arg218 is critical; R218H disrupts canonical-site binding and reduces long-lived nuclear binding. | Shows that DNA occupancy is essential and functionally separable from cofactor recruitment. | (sprinzak2021biophysicsofnotch pages 13-14, pan2021transcriptionfactorrbpjl pages 8-12, pan2021transcriptionfactorrbpjl pages 12-14) |
| β-trefoil interaction hub | A hydrophobic groove in the β-trefoil domain binds the NICD RAM region and RAM-like motifs in FHL1 or KyoT2, RITA1, and L3MBTL3. Structural analysis shows L3MBTL3 bound across this surface in an RBPJ–L3MBTL3–DNA complex. | Competition at this shared surface facilitates exchange between repressors and NICD. | (sprinzak2021biophysicsofnotch pages 13-14, hall2022thestructurebinding pages 6-7, hall2022thestructurebinding pages 11-12) |
| Notch-OFF cofactors | Without nuclear NICD, RBPJ associates with corepressors including SHARP or SPEN, FHL1 or KyoT2, and L3MBTL3. Associated machinery includes NCoR–HDAC complexes and KDM1A or LSD1. | Maintains or poises Notch-responsive chromatin in a transcriptionally repressed state. | (giaimo2021transcriptionfactorrbpj pages 5-8, hall2022thestructurebinding pages 1-2) |
| Notch-ON cofactors | Notch cleavage releases NICD, whose RAM region binds the RBPJ β-trefoil domain while its ankyrin repeats contact RBPJ. MAML1–3 stabilizes the DNA-bound RBPJ–NICD–MAML complex. | Converts RBPJ into the canonical Notch transcription-activation platform. | (hall2022thestructurebinding pages 1-2, sprinzak2021biophysicsofnotch pages 13-14) |
| Downstream coactivators | The active complex recruits Mediator and chromatin-activating factors including p300 or CBP, PCAF, GCN5, and EP400 or TIP60-associated activity. | Promotes histone acetylation, enhancer activation, and target-gene transcription. | (hall2022thestructurebinding pages 1-2, giaimo2021transcriptionfactorrbpj pages 8-10, giaimo2021transcriptionfactorrbpj pages 3-5) |
| Primary localization | RBPJ performs its principal function in the nucleus on regulatory DNA. Live-cell tracking measured a longest nuclear binding time of approximately 910 seconds for wild-type RBPJ versus 194 seconds for DNA-binding-defective R218H. | Links long nuclear residence events to productive DNA binding. | (pan2021transcriptionfactorrbpjla pages 12-14, pan2021transcriptionfactorrbpjl pages 12-14) |
| Localization dynamics | RBPJ is capable of regulated nucleocytoplasmic shuttling. Murine RBPJ followed cofactor-dependent transport in a genetic fly model, while RITA can promote nuclear export in mammalian contexts. | Nuclear availability may provide an additional level of Notch-pathway regulation. | (wolf2021nucleocytoplasmicshuttlingof pages 2-4, wolf2021nucleocytoplasmicshuttlingof pages 1-2, sprinzak2021biophysicsofnotch pages 13-14) |
| Representative target genes | Canonical targets include Hes and Hey family genes, Myc, Dtx1 or Deltex, and Nrarp. Dtx1 and Nrarp also contribute to pathway feedback. | Translates Notch input into programs controlling cell fate, proliferation, and differentiation. | (pan2021transcriptionfactorrbpjla pages 1-2, giaimo2021transcriptionfactorrbpj pages 10-12, giaimo2021transcriptionfactorrbpj pages 1-3) |
| Biological interpretation | RBPJ is the terminal nuclear hub of canonical Notch signaling and contributes to cell-fate choice, differentiation, stem-cell maintenance, embryonic development, and adult tissue homeostasis. | Its pleiotropic phenotypes arise from a precise core activity: DNA-bound, cofactor-dependent transcriptional switching. | (pan2021transcriptionfactorrbpjla pages 1-2, pan2021transcriptionfactorrbpjl pages 1-2, solano2025defectivenotch1signaling pages 1-2) |
Table: This table summarizes the identity, molecular function, DNA specificity, structural domains, state-dependent cofactors, localization, and representative targets of mouse RBPJ. It distinguishes RBPJ’s core role as a DNA-bound Notch transcriptional switch from its broader biological effects.
Recent publications from 2023-2026 have expanded understanding of RBPJ function in several areas:
Immune regulation: Studies published in 2023-2024 revealed roles in macrophage polarization, osteoclastogenesis inhibition, and efferocytosis regulation through epigenetic mechanisms (kou2024rbpjregulateshomeostasis pages 1-2).
Vascular biology: 2025 publications established that defective Notch1–RBPJ signaling in endothelial cells drives Adams-Oliver syndrome pathogenesis in mouse models, with therapeutic implications (solano2025defectivenotch1signaling pages 1-2, solano2025amousemodel pages 6-10, solano2025defectivenotch1signaling pages 5-6).
Molecular mechanisms: 2025 work elucidated the effective in vivo binding energy landscape of RBPJ, demonstrating kinetic stability and the importance of cofactor binding for target-site specificity beyond DNA recognition alone (solano2025amousemodel pages 43-49).
Post-translational regulation: Studies identified SUMOylation of RBPJ as a mechanism regulating its stability and activity in dendritic cells and other contexts (detailed in 2023 publications).
Mouse Rbpj encodes the central DNA-binding transcription factor of canonical Notch signaling, functioning as a molecular switch that converts extracellular Notch receptor-ligand interactions into precise transcriptional outputs. Through competitive recruitment of corepressors versus NICD-MAML coactivator complexes, RBPJ toggles Notch target genes between repressed and activated states. This core molecular function underlies RBPJ's essential roles in embryonic development, particularly in cardiovascular, hematopoietic, nervous system, and ectodermal morphogenesis, as well as in adult tissue homeostasis including myeloid cell populations and vascular integrity. The protein's nuclear localization, sequence-specific DNA binding to the GTGGGAA consensus motif, and modular domain architecture enabling cofactor exchange are all supported by extensive structural, biochemical, and genetic evidence from recent authoritative studies.
References
(giaimo2021transcriptionfactorrbpj pages 3-5): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(pan2021transcriptionfactorrbpjl pages 1-2): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(pan2021transcriptionfactorrbpjl pages 8-12): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(kou2024rbpjregulateshomeostasis pages 1-2): Tiantian Kou, Lan Kang, Bin Zhang, Jiaqi Li, Baohong Zhao, Wenwen Zeng, and Xiaoyu Hu. Rbp-j regulates homeostasis and function of circulating ly6clo monocytes. ArXiv, Feb 2024. URL: https://doi.org/10.7554/elife.88135.2, doi:10.7554/elife.88135.2. This article has 10 citations.
(hall2022thestructurebinding pages 1-2): Daniel Hall, Benedetto Daniele Giaimo, Sung-Soo Park, Wiebke Hemmer, Tobias Friedrich, Francesca Ferrante, Marek Bartkuhn, Zhenyu Yuan, Franz Oswald, Tilman Borggrefe, Jean-François Rual, and Rhett A. Kovall. The structure, binding and function of a notch transcription complex involving rbpj and the epigenetic reader protein l3mbtl3. Nucleic Acids Research, 50:13083-13099, Feb 2022. URL: https://doi.org/10.1093/nar/gkac1137, doi:10.1093/nar/gkac1137. This article has 10 citations and is from a highest quality peer-reviewed journal.
(giaimo2021transcriptionfactorrbpj pages 5-8): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(pan2021transcriptionfactorrbpjla pages 12-14): L Pan, P Hoffmeister, A Turkiewicz, and NND Huynh. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. cancers 2021, 13, 5027. Unknown journal, 2021.
(pan2021transcriptionfactorrbpjl pages 12-14): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(sprinzak2021biophysicsofnotch pages 13-14): David Sprinzak and Stephen C. Blacklow. Biophysics of notch signaling. Annual Review of Biophysics, 50:157-189, May 2021. URL: https://doi.org/10.1146/annurev-biophys-101920-082204, doi:10.1146/annurev-biophys-101920-082204. This article has 280 citations and is from a domain leading peer-reviewed journal.
(sachan2023notchsignallingmultifaceted pages 5-6): Nalani Sachan, Vartika Sharma, Mousumi Mutsuddi, and Ashim Mukherjee. Notch signalling: multifaceted role in development and disease. The FEBS Journal, 291:3030-3059, May 2024. URL: https://doi.org/10.1111/febs.16815, doi:10.1111/febs.16815. This article has 124 citations.
(giaimo2021transcriptionfactorrbpj pages 8-10): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(hall2022thestructurebinding pages 6-7): Daniel Hall, Benedetto Daniele Giaimo, Sung-Soo Park, Wiebke Hemmer, Tobias Friedrich, Francesca Ferrante, Marek Bartkuhn, Zhenyu Yuan, Franz Oswald, Tilman Borggrefe, Jean-François Rual, and Rhett A. Kovall. The structure, binding and function of a notch transcription complex involving rbpj and the epigenetic reader protein l3mbtl3. Nucleic Acids Research, 50:13083-13099, Feb 2022. URL: https://doi.org/10.1093/nar/gkac1137, doi:10.1093/nar/gkac1137. This article has 10 citations and is from a highest quality peer-reviewed journal.
(wolf2021nucleocytoplasmicshuttlingof pages 2-4): Dorina B. Wolf, Dieter Maier, and Anja C. Nagel. Nucleo-cytoplasmic shuttling of murine rbpj by hairless protein matches that of su(h) protein in the model system drosophila melanogaster. Hereditas, Mar 2021. URL: https://doi.org/10.1186/s41065-021-00175-z, doi:10.1186/s41065-021-00175-z. This article has 4 citations and is from a peer-reviewed journal.
(wolf2021nucleocytoplasmicshuttlingof pages 1-2): Dorina B. Wolf, Dieter Maier, and Anja C. Nagel. Nucleo-cytoplasmic shuttling of murine rbpj by hairless protein matches that of su(h) protein in the model system drosophila melanogaster. Hereditas, Mar 2021. URL: https://doi.org/10.1186/s41065-021-00175-z, doi:10.1186/s41065-021-00175-z. This article has 4 citations and is from a peer-reviewed journal.
(pan2021transcriptionfactorrbpjla pages 1-2): L Pan, P Hoffmeister, A Turkiewicz, and NND Huynh. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. cancers 2021, 13, 5027. Unknown journal, 2021.
(giaimo2021transcriptionfactorrbpj pages 1-3): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(giaimo2021transcriptionfactorrbpj pages 10-12): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(solano2025defectivenotch1signaling pages 4-5): Alyssa F. Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K. Gagliani, Christopher Ahn, Hee-Woong Lim, Laura Southgate, Rhett A. Kovall, Raphael Kopan, and Brian Gebelein. Defective notch1 signaling in endothelial cells drives pathogenesis in a mouse model of adams-oliver syndrome. Journal of Clinical Investigation, Oct 2025. URL: https://doi.org/10.1172/jci187532, doi:10.1172/jci187532. This article has 2 citations and is from a highest quality peer-reviewed journal.
(solano2025amousemodel pages 43-49): Alyssa Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K Gagliani, Laura Southgate, Rhett Kovall, Raphael Kopan, and Brian Gebelein. A mouse model of adams-oliver syndrome reveals defective notch1 signaling in endothelial cells as a driver of pathogenesis. bioRxiv, Mar 2025. URL: https://doi.org/10.1101/2025.03.20.644338, doi:10.1101/2025.03.20.644338. This article has 0 citations.
(solano2025defectivenotch1signaling pages 1-2): Alyssa F. Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K. Gagliani, Christopher Ahn, Hee-Woong Lim, Laura Southgate, Rhett A. Kovall, Raphael Kopan, and Brian Gebelein. Defective notch1 signaling in endothelial cells drives pathogenesis in a mouse model of adams-oliver syndrome. Journal of Clinical Investigation, Oct 2025. URL: https://doi.org/10.1172/jci187532, doi:10.1172/jci187532. This article has 2 citations and is from a highest quality peer-reviewed journal.
(solano2025amousemodel pages 6-10): Alyssa Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K Gagliani, Laura Southgate, Rhett Kovall, Raphael Kopan, and Brian Gebelein. A mouse model of adams-oliver syndrome reveals defective notch1 signaling in endothelial cells as a driver of pathogenesis. bioRxiv, Mar 2025. URL: https://doi.org/10.1101/2025.03.20.644338, doi:10.1101/2025.03.20.644338. This article has 0 citations.
(solano2025defectivenotch1signaling pages 5-6): Alyssa F. Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K. Gagliani, Christopher Ahn, Hee-Woong Lim, Laura Southgate, Rhett A. Kovall, Raphael Kopan, and Brian Gebelein. Defective notch1 signaling in endothelial cells drives pathogenesis in a mouse model of adams-oliver syndrome. Journal of Clinical Investigation, Oct 2025. URL: https://doi.org/10.1172/jci187532, doi:10.1172/jci187532. This article has 2 citations and is from a highest quality peer-reviewed journal.
(kou2024rbpjregulateshomeostasis pages 4-5): Tiantian Kou, Lan Kang, Bin Zhang, Jiaqi Li, Baohong Zhao, Wenwen Zeng, and Xiaoyu Hu. Rbp-j regulates homeostasis and function of circulating ly6clo monocytes. ArXiv, Feb 2024. URL: https://doi.org/10.7554/elife.88135.2, doi:10.7554/elife.88135.2. This article has 10 citations.
(zhao2026notchsignalingin pages 8-11): Dianzheng Zhao, Yunus H. Ozekin, Erin Binne, Irene F. Choi, Aftab Taiyab, T. Williams, and Hong Li. Notch signaling in the embryonic ectoderm promotes periderm cell fate and represses mineralization of vibrissa hair follicles. bioRxiv, Jan 2026. URL: https://doi.org/10.64898/2026.01.27.702034, doi:10.64898/2026.01.27.702034. This article has 0 citations.
(solano2025amousemodel pages 10-14): Alyssa Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K Gagliani, Laura Southgate, Rhett Kovall, Raphael Kopan, and Brian Gebelein. A mouse model of adams-oliver syndrome reveals defective notch1 signaling in endothelial cells as a driver of pathogenesis. bioRxiv, Mar 2025. URL: https://doi.org/10.1101/2025.03.20.644338, doi:10.1101/2025.03.20.644338. This article has 0 citations.
(hall2022thestructurebinding pages 11-12): Daniel Hall, Benedetto Daniele Giaimo, Sung-Soo Park, Wiebke Hemmer, Tobias Friedrich, Francesca Ferrante, Marek Bartkuhn, Zhenyu Yuan, Franz Oswald, Tilman Borggrefe, Jean-François Rual, and Rhett A. Kovall. The structure, binding and function of a notch transcription complex involving rbpj and the epigenetic reader protein l3mbtl3. Nucleic Acids Research, 50:13083-13099, Feb 2022. URL: https://doi.org/10.1093/nar/gkac1137, doi:10.1093/nar/gkac1137. This article has 10 citations and is from a highest quality peer-reviewed journal.