Arabidopsis thaliana TFL1 (AT5G03840) encodes a PEBP/CETS-family protein that antagonizes FT/TSF floral activation to maintain indeterminate inflorescence meristem identity and restrain premature floral meristem conversion. TFL1 is a non-DNA-binding transcriptional regulatory mediator: genetic, fusion-protein, and BiFC evidence support FD-dependent transcriptional repression in the nucleus, while cytoplasmic localization and intercellular mobility support movement through meristem tissues. A separate PSV/endomembrane trafficking study supports vacuolar trafficking and membrane/vesicle localization, but this is best treated as non-core relative to the conserved flowering-time and inflorescence-architecture role.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: Cytoplasmic localization is consistent with UniProt subcellular-location mapping and with experimental reports that TFL1 is present in both nucleus and cytoplasm and moves between cells in meristems. Reason: Although this entry is computational, the same localization is supported by IDA evidence and is relevant to TFL1 mobility and nucleocytoplasmic shuttling. Supporting Evidence: PMID:21890645 We demonstrated interaction between TFL1 and FD in the nucleus by a BiFC assay and showed that the TFL1 protein is present in nucleus and cytoplasm file:ARATH/TFL1/TFL1-deep-research-falcon.md Subcellular localization relevant to function: TFL1-FD interaction is detected in the nucleus, consistent with a transcriptional regulatory mechanism. |
| GO:0010022 meristem determinacy | IGI PMID:30943325 Genetic interactions reveal the antagonistic roles of FT/TSF... | ACCEPT | Summary: Genetic interaction evidence supports a role for TFL1, antagonistic to FT/TSF, in determining inflorescence meristem identity and whether the shoot apex remains indeterminate or forms a terminal flower. Reason: Meristem determinacy is a core biological process for TFL1: loss of TFL1 produces terminal flowers, and FT/TSF/TFL1 genetic combinations alter inflorescence meristem identity. Supporting Evidence: PMID:30943325 we examined the genetic interactions of FLOWERING LOCUS T (FT)/TWIN SISTER OF FT (TSF) and TERMINAL FLOWER 1 (TFL1) in the determination of inflorescence meristem identity in Arabidopsis thaliana. PMID:30943325 we proposed that FT/TSF and TFL1 play antagonistic roles in the determination of inflorescence meristem identity file:ARATH/TFL1/TFL1-deep-research-falcon.md Core definition and biological role: Arabidopsis TFL1 is a member of the phosphatidylethanolamine-binding protein (PEBP) family and functions as a key negative regulator of flowering and a regulator of inflorescence meristem (IM) identity/indeterminacy. |
| GO:0005737 cytoplasm | ISM GO_REF:0000122 | ACCEPT | Summary: The AtSubP cytoplasm prediction is consistent with direct localization evidence and with TFL1 mobility in meristems. Reason: Retain this computational annotation because independent experimental studies support cytoplasmic TFL1 as part of its mobile, shuttling behavior. Supporting Evidence: PMID:17369370 TFL1 mRNA is restricted to the inner cells of the meristem, but TFL1 protein is small and mobile PMID:21890645 These findings suggest that TFL1 is a nucleocytoplasmic shuttling protein that may play a role in FD-dependent transcription. |
| GO:0003712 transcription coregulator activity | IMP PMID:21890645 Arabidopsis TERMINAL FLOWER1 is involved in the regulation o... | MODIFY | Summary: The evidence supports transcriptional coregulation, but the term is less specific than the experimentally supported repressive role of TFL1 in FD-dependent transcription. Reason: Hanano and Goto show that TFL1-SRDX behaves like native TFL1, TFL1-VP16 causes opposite/dominant phenotypes, and TFL1 interacts with FD in the nucleus. This supports the more specific molecular function transcription corepressor activity rather than generic transcription coregulator activity. Proposed replacements: transcription corepressor activity Supporting Evidence: PMID:21890645 TFL1-SRDX acts as a native TFL1, suggesting that the native TFL1 functions as a transcriptional repressor or a carrier of a repressor. PMID:21890645 We conclude that TFL1 negatively modulates the FD-dependent transcription of target genes to fine-tune flowering time and the development of the inflorescence meristem. PMID:21890645 TFL1 interacted with FD in the cell nucleus, as shown by bimolecular fluorescence complementation experiments. file:ARATH/TFL1/TFL1-deep-research-falcon.md Primary molecular function: FD-dependent transcriptional repression |
| GO:0005634 nucleus | IDA PMID:21890645 Arabidopsis TERMINAL FLOWER1 is involved in the regulation o... | ACCEPT | Summary: TFL1 was detected in the nucleus through BiFC interaction with FD and in localization assays, consistent with its transcriptional repression mechanism. Reason: Nuclear localization is central to the FD-dependent transcriptional regulatory model and is directly supported by the cited study. Supporting Evidence: PMID:21890645 TFL1 interacted with FD in the cell nucleus, as shown by bimolecular fluorescence complementation experiments. PMID:21890645 We demonstrated interaction between TFL1 and FD in the nucleus by a BiFC assay and showed that the TFL1 protein is present in nucleus and cytoplasm |
| GO:0005737 cytoplasm | IDA PMID:21890645 Arabidopsis TERMINAL FLOWER1 is involved in the regulation o... | ACCEPT | Summary: Hanano and Goto directly report that TFL1 is present in cytoplasm as well as nucleus, fitting the model that TFL1 shuttles while regulating FD-dependent transcription. Reason: Cytoplasmic localization is experimentally supported and relevant to the intercellular and nucleocytoplasmic movement of TFL1. Supporting Evidence: PMID:21890645 We demonstrated interaction between TFL1 and FD in the nucleus by a BiFC assay and showed that the TFL1 protein is present in nucleus and cytoplasm PMID:21890645 These findings suggest that TFL1 is a nucleocytoplasmic shuttling protein that may play a role in FD-dependent transcription. |
| GO:0005737 cytoplasm | IDA PMID:17369370 TERMINAL FLOWER1 is a mobile signal controlling Arabidopsis ... | ACCEPT | Summary: Conti and Bradley support TFL1 as a small mobile protein that moves across meristem cells; together with Hanano and Goto's direct localization data, this supports cytoplasmic TFL1. Reason: The original cached text mainly supports mobility rather than the exact subcellular compartment, but the cytoplasm annotation is supported by additional direct evidence and is coherent with TFL1 cell-to-cell movement. Supporting Evidence: PMID:17369370 We reveal that the TFL1 protein is a mobile signal that becomes evenly distributed across the meristem. PMID:17369370 TFL1 moves from inner cells to outer cells but is restricted from lateral primordia. PMID:21890645 We demonstrated interaction between TFL1 and FD in the nucleus by a BiFC assay and showed that the TFL1 protein is present in nucleus and cytoplasm |
| GO:0005773 vacuole | IDA PMID:18003908 The shoot meristem identity gene TFL1 is involved in flower ... | KEEP AS NON CORE | Summary: Sohn et al. report TFL1 localization to endomembrane compartments and, in the full-text figure description, to the vacuole/tonoplast. This supports the localization but it is not the primary flowering/meristem regulatory function of TFL1. Reason: Retain as a supported non-core localization. The cached local text is abstract-level; the more specific vacuole localization comes from the online full-text figure description, so the detailed evidence is flagged as full text unavailable in the local cache. Supporting Evidence: PMID:18003908 TFL1 localizes to endomembrane compartments and colocalizes with the putative delta-subunit of the AP-3 adapter complex. |
| GO:0005886 plasma membrane | IDA PMID:18003908 The shoot meristem identity gene TFL1 is involved in flower ... | KEEP AS NON CORE | Summary: Full-text localization evidence from Sohn et al. reports TFL1 at the plasma membrane as part of an endomembrane/vesicle localization pattern, but this is secondary to the core FD-dependent meristem regulatory role. Reason: Retain as non-core because the localization is supported, but the central gene function is not a plasma-membrane activity. The detailed localization text is not present in the cached publication extract. Supporting Evidence: PMID:18003908 TFL1 localizes to endomembrane compartments and colocalizes with the putative delta-subunit of the AP-3 adapter complex. |
| GO:0006623 protein targeting to vacuole | IMP PMID:18003908 The shoot meristem identity gene TFL1 is involved in flower ... | KEEP AS NON CORE | Summary: The tfl1-19/mtv5 mutant was identified in a protein storage vacuole trafficking screen and is defective in trafficking proteins to the PSV, supporting a role in vacuolar protein targeting. Reason: The annotation is experimentally supported, but later mechanistic work and the broader literature identify TFL1's primary conserved function as FD-dependent repression of flowering and inflorescence-meristem genes. PSV trafficking should therefore be retained as non-core. Supporting Evidence: PMID:18003908 The tfl1-19/mtv5 (for "modified traffic to the vacuole") mutant is specifically defective in trafficking of proteins to the PSV. PMID:18003908 TFL1 localizes to endomembrane compartments and colocalizes with the putative delta-subunit of the AP-3 adapter complex. PMID:21890645 It is possible that TFL1 has pleiotropic functions, including that of a carrier of proteins from the nucleus to PSVs. |
| GO:0031982 vesicle | IDA PMID:18003908 The shoot meristem identity gene TFL1 is involved in flower ... | KEEP AS NON CORE | Summary: The full-text localization evidence reports dense vesicle/compartment labeling and colocalization with an AP-3 adapter marker, supporting vesicle localization as part of a PSV-trafficking context. Reason: Vesicle localization is supported but represents a non-core localization relative to the established transcriptional/meristem identity role of TFL1. The specific vesicle text is not present in the cached publication extract. Supporting Evidence: PMID:18003908 TFL1 localizes to endomembrane compartments and colocalizes with the putative delta-subunit of the AP-3 adapter complex. |
| GO:0009910 negative regulation of flower development | IMP PMID:12324621 A Mutation in the Arabidopsis TFL1 Gene Affects Inflorescenc... | ACCEPT | Summary: TFL1 loss of function causes early flowering and conversion of the normally indeterminate inflorescence into a terminal floral meristem, supporting TFL1 as a negative regulator of floral development at the shoot apex. Reason: This captures a core biological role of TFL1: preventing premature floral meristem fate and maintaining inflorescence development. Supporting Evidence: PMID:12324621 The tfl1-1 mutation causes early flowering and limits the development of the normally indeterminate inflorescence by promoting the formation of a terminal floral meristem. PMID:12324621 Our results suggest that tfl1-1 perturbs the establishment and maintenance of the inflorescence meristem. PMID:21890645 TFL1 negatively modulates the FD-dependent transcription of target genes to fine-tune flowering time and the development of the inflorescence meristem. |
| GO:0009744 response to sucrose | IMP PMID:11553753 Effects of sugar on vegetative development and floral transi... | MARK AS OVER ANNOTATED | Summary: The sucrose paper reports that sucrose effects on flowering were more pronounced in tfl1 mutants, but it does not establish TFL1 as a direct sucrose-response factor. The phenotype is better interpreted through TFL1's role in flowering-time/meristem phase transition. Reason: A differential flowering response in a tfl1 mutant background is insufficient to make response to sucrose a core or direct TFL1 process. This is a broad physiological response annotation derived from a secondary phenotype. Supporting Evidence: PMID:11553753 This inhibition was more pronounced in tfl1, an early flowering mutant, than in the wild type. PMID:11553753 These results suggest that sugar may affect floral transition by activating or inhibiting genes that act to control floral transition, depending on the concentration of sugars, the genetic background of the plants, and when the sugar is introduced. |
| GO:0010077 maintenance of inflorescence meristem identity | IMP PMID:21890645 Arabidopsis TERMINAL FLOWER1 is involved in the regulation o... | NEW | Summary: TFL1 acts in the centre of the inflorescence meristem to keep it indeterminate; tfl1 loss-of-function inflorescences become determinate and end in a terminal flower. Reason: Not in GOA, which carries the broader meristem determinacy (GO:0010022) and negative regulation of flower development (GO:0009910). TFL1 itself performs work in this process: it is a corepressor acting with FD in the inflorescence meristem to repress floral meristem identity targets, and a TFL1-SRDX repressor fusion complements tfl1, so the protein's own repressive activity maintains inflorescence meristem identity. Comparator check: other inflorescence/floral meristem identity regulators (LFY, FUL, SOC1) carry GO:0010077 in Arabidopsis GOA, so the term is used for transcriptional regulators acting in the meristem. GO:0010077 is not an ancestor or descendant of the existing GO:0010022 or GO:0009910 terms. The comparators and TFL1's neighbouring rows use acts_upstream_of_or_within; involved_in is chosen here because the TFL1-SRDX result shows TFL1's own corepressor activity in the meristem doing the maintaining work. Supporting Evidence: PMID:21890645 In addition, the inflorescences of tfl1 mutants are converted from indeterminate into determinate; they produce reduced numbers of flower buds and possess terminal flowers at the shoot apices PMID:21890645 We conclude that TFL1 negatively modulates the FD-dependent transcription of target genes to fine-tune flowering time and the development of the inflorescence meristem. PMID:17369370 This novel feedback signaling mechanism would ensure that shoot meristem identity is maintained and the appropriate inflorescence architecture develops. |
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Download this section (compressed HTML)Q: Is the PSV/endomembrane trafficking phenotype a direct conserved activity of endogenous TFL1 in meristems, or a secondary/pleiotropic consequence of TFL1 perturbation and tagging context?
Suggested experts: Natasha V. Raikhel, Elena Rojo, Francisco Madueño
Q: Which FD/FDP-bound genomic targets and corepressor or 14-3-3 partners are directly controlled by TFL1 in the inflorescence meristem?
Suggested experts: Sachiko Hanano, Koji Goto, Ji Hoon Ahn
Experiment: Perform FD CUT&RUN or ChIP-seq and nascent RNA profiling in matched wild type, tfl1 loss-of-function, TFL1 rescue, and FT/TSF perturbation backgrounds at the floral transition to identify direct FD targets whose expression is TFL1-dependent.
Hypothesis: TFL1 represses a defined subset of FD-bound floral meristem identity targets at the inflorescence meristem.
Type: genomics
Experiment: Generate native-locus fluorescent and proximity-labeling TFL1 alleles that fully rescue tfl1 phenotypes, then quantify meristem localization, FD/14-3-3 proximity, and AP-3/PSV marker colocalization under identical imaging conditions.
Hypothesis: Endogenous TFL1 occupies distinct nuclear/cytoplasmic and endomembrane pools, with only a subset contributing to PSV trafficking.
Type: cell_biology
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