| Citation (first author, year) | Type | Main finding relevant to Trf4/TRAMP | Methods | URL/DOI | Why it matters for functional annotation |
|---|---|---|---|---|---|
| Vaňáčová, 2005 | Primary | Established that yeast PAP2/TRF4 encodes the catalytic subunit of a non-canonical poly(A) polymerase complex with Air1/2 and Mtr4 that polyadenylates aberrant RNAs and stimulates nuclear exosome-dependent decay, especially defective tRNAs (pqac-00000001, pqac-00000003, pqac-00000007, pqac-00000050, pqac-00000056) | Affinity purification/TAP, recombinant reconstitution, polyadenylation assays, two-hybrid, reverse-tag copurification, coupled degradation assays | https://doi.org/10.1371/journal.pbio.0030189 | Foundational evidence that PAP2/TRF4 is an RNA polymerase in nuclear RNA surveillance, not a DNA polymerase, and defines its core partners and primary biochemical role. |
| Schmidt, 2012 | Primary | Showed that Air1 and Air2 help determine differential TRAMP substrate specificity, with TRAMP4/5 complexes targeting overlapping but distinct nuclear RNA sets (pqac-00000005, pqac-00000025) | Genetics, deep sequencing/transcript profiling, mutant analysis | https://doi.org/10.1261/rna.033431.112 | Important for annotating Trf4 function as part of a specificity-determining complex rather than as a stand-alone polymerase. |
| Schmidt & Butler, 2013 | Review | Synthesized evidence that TRAMP is a nuclear Trf4/5–Air1/2–Mtr4 complex that oligoadenylates RNAs for Rrp6/core-exosome processing or decay; discussed localization, subunit interfaces, and substrate scope (pqac-00000006, pqac-00000013, pqac-00000021, pqac-00000024, pqac-00000028, pqac-00000044, pqac-00000057) | Review of structural, genetic, biochemical, and GFP-localization studies | https://doi.org/10.1002/wrna.1155 | Best integrative source for functional annotation of biological process, localization, and pathway context. |
| Stuparevic, 2013 | Primary | Reported cotranscriptional recruitment of TRAMP components and exosome cofactors Rrp47/Mpp6, linking Trf4/Trf5 complexes to surveillance of aberrant mRNPs during transcription (pqac-00000054) | Chromatin/cotranscriptional recruitment analysis, mutant studies | Publication details incomplete in retrieved evidence | Supports annotation of Trf4 in cotranscriptional nuclear surveillance and exosome cofactor networks. |
| Das, 2021 | Primary | Reconstitution showed that Trf4 polyadenylation, Mtr4 helicase activity, and Rrp6/Dis3 nucleases each contribute to substrate discrimination, establishing a proofreading-like model for nuclear RNA quality control (pqac-00000000, pqac-00000012, pqac-00000027, pqac-00000052) | In vitro reconstitution biochemistry, mutational analysis, exosome/TRAMP degradation assays | https://doi.org/10.1073/pnas.2024846118 | Refines annotation from simple “marks RNAs for decay” to a coordinated quality-control mechanism that distinguishes stable vs aberrant RNAs. |
| Villa & Porrua, 2023 | Review | Highlighted TRAMP as the principal nuclear exosome cofactor for pervasive transcript decay and described mechanistic coupling of Trf4–Air2 to NNS termination via Nrd1 recognition of a Trf4 motif (pqac-00000016, pqac-00000026, pqac-00000036, pqac-00000038, pqac-00000051) | Review of recent mechanistic and genomics studies | https://doi.org/10.1111/febs.16530 | Useful for current annotation of pathway integration: Trf4 links transcription termination, pervasive ncRNA control, and exosome targeting. |
| DeMario, 2023 | Primary | Provided recent quantitative evidence that Air2 is especially important for TRAMP targeting of pre-snoRNAs and mapped mutant-dependent changes in poly(A) peaks and tail lengths, supporting roles in late snoRNA processing and surveillance (pqac-00000035, pqac-00000046, pqac-00000049) | 3′ end sequencing, Oxford Nanopore direct RNA/cDNA sequencing, mutant genetics | Publication details incomplete in retrieved evidence | Adds modern transcriptome-wide support for annotating Trf4/TRAMP in snoRNA maturation/surveillance and gives recent quantitative context. |
| Elder, 2024 | Review | Summarized current understanding that TRAMP (Trf4/Air2/Mtr4) selectively polyadenylates hypomodified tRNAs and cooperates with Rrp6 and Dis3 for their degradation (pqac-00000048) | Review of biochemical and genetic studies | https://doi.org/10.1016/j.tig.2024.03.007 | Reinforces that tRNA quality control is one of the clearest, best-supported substrate-specific functions for Trf4. |
| Rambout & Maquat, 2024 | Review | Positioned TRAMP within nuclear mRNA decay networks, including degradation of readthrough and aberrantly processed transcripts, and noted that yeast TRAMP-mediated decay can occur even when new oligoadenylation is not always required (pqac-00000039, pqac-00000043) | Review of nuclear RNA decay pathways and comparative mechanistic studies | https://doi.org/10.1038/s41576-024-00712-2 | Expands annotation beyond ncRNAs/tRNAs to broader nuclear mRNA surveillance and termination-coupled decay. |
| Sterrett, 2023 | Primary | Used yeast to probe the critical exosome–Mtr4 interface in vivo, showing that disrupted Mtr4–exosome interaction causes accumulation of exosome target RNAs (pqac-00000021) | Yeast disease-model genetics, biochemical interaction assays | https://doi.org/10.1093/g3journal/jkad049 | Relevant because Trf4 function depends on Mtr4-mediated delivery of oligoadenylated RNAs to the exosome. |
| Yim, 2023 | Primary | Showed conserved Mtr4 C-terminal residues coordinate helicase activity and exosome interactions, including effects on RNA degradation in assays with TRAMP components (pqac-00000027) | Mutagenesis, helicase assays, in vitro RNA degradation assays | https://doi.org/10.1021/acs.biochem.3c00401 | Helps interpret Trf4 function mechanistically through its essential helicase partner Mtr4 and exosome coupling. |


*Table: This table compiles foundational and recent sources used to functionally annotate yeast PAP2/TRF4, emphasizing direct evidence for catalytic activity, substrate specificity, localization, and pathway context. It is useful for distinguishing well-established roles from newer 2023–2024 mechanistic updates.*