TFIIF is a general transcription initiation factor that binds to RNA polymerase II and helps to recruit it to the initiation complex in collaboration with TFIIB. It promotes transcription elongation.
J. Biol. Chem. 274, 22387-22392 (1999)[PubMed:10428810]
The largest subunit of the human basal transcription factor TFIIFalpha (also called RAP74) was reported previously to be the target of some phospho/dephosphorylation process. We show that TFIIFalpha possesses a serine/threonine kinase activity, allowing an autophosphorylation of the two residues at position serine 385 and threonine 389. Mutation analysis strongly suggests that autophosphorylation of both sites regulates the transcription elongation process. Moreover we also evidence three additional phosphorylation sites located at positions 207-230, 271-283, and 335-344. These sites are phosphorylated by casein kinase II-like kinases and TAF(II)250, a component of TFIID.
Catalysis of a biochemical reaction at physiological temperatures. In biologically catalyzed reactions, the reactants are known as substrates, and the catalysts are naturally occurring macromolecular substances known as enzymes. Enzymes possess specific binding sites for substrates, and are usually composed wholly or largely of protein, but RNA that has catalytic activity (ribozyme) is often also regarded as enzymatic.
The transcription and processing of pre-mRNA in eukaryotic cells are regulated in part by reversible phosphorylation of the C-terminal domain of the largest RNA polymerase (RNAP) II subunit. The CTD phosphatase, FCP1, catalyzes the dephosphorylation of RNAP II and is thought to play a major role in polymerase recycling. This study describes a family of small CTD phosphatases (SCPs) that preferentially catalyze the dephosphorylation of Ser5 within the consensus repeat. The preferred substrate for SCP1 is RNAP II phosphorylated by TFIIH. Like FCP1, the activity of SCP1 is enhanced by the RAP74 subunit of TFIIF. Expression of SCP1 inhibits activated transcription from a number of promoters, whereas a phosphatase-inactive mutant of SCP1 enhances transcription. Accordingly, SCP1 may play a role in the regulation of gene expression, possibly by controlling the transition from initiation/capping to processive transcript elongation.
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
Evidence
1:
Inferred from Physical InteractionUniProtKB
RMP was reported to regulate transcription via competing with HBx to bind the general transcription factor IIB (TFIIB) and interacting with RPB5 subunit of RNA polymerase II as a corepressor of transcription regulator. However, our present research uncovered that RMP also regulates the transcription through interaction with the general transcription factors IIF (TFIIF), which assemble in the preinitiation complex and function in both transcription initiation and elongation. With in vitro pull-down assay and Far-Western analysis, we demonstrated that RMP could bind with bacterially expressed recombinant RAP30 and RAP74 of TFIIF subunits. In the immunoprecipitation assay in COS1 cells cotransfected with FLAG-tagged RMP or its mutants, GST-fused RAP30 and RAP74 were co-immunoprecipitated with RMP in approximately equal molar ratio, which suggests that RAP30 and RAP74 interact with RMP as a TFIIF complex. Interestingly both RAP30 and RAP74 interact with the same domain (D5) of the C-terminal RMP of 118-amino-acid residuals which overlaps with its TFIIB-binding domain. Internal deletion of D5 region of RMP abolished its binding ability with both subunits of TFIIF, while D5 domain alone was sufficient to interact with TFIIF subunits. The result of luciferase assay showed that overexpression of RMP, but not the mutant RMP lacking D5 region, suppressed the transcription activated by Gal-VP16, suggesting that interaction with TFIIF is required for RMP to suppress the activated transcription. The interaction between RMP and TFIIF may be an additional passway for RMP to regulate the transcription, or alternatively TFIIF may cooperate with RPB5 and TFIIB for the corepressor function of RMP.
Evidence
2:
Inferred from Physical InteractionUniProtKB
The transcription and processing of pre-mRNA in eukaryotic cells are regulated in part by reversible phosphorylation of the C-terminal domain of the largest RNA polymerase (RNAP) II subunit. The CTD phosphatase, FCP1, catalyzes the dephosphorylation of RNAP II and is thought to play a major role in polymerase recycling. This study describes a family of small CTD phosphatases (SCPs) that preferentially catalyze the dephosphorylation of Ser5 within the consensus repeat. The preferred substrate for SCP1 is RNAP II phosphorylated by TFIIH. Like FCP1, the activity of SCP1 is enhanced by the RAP74 subunit of TFIIF. Expression of SCP1 inhibits activated transcription from a number of promoters, whereas a phosphatase-inactive mutant of SCP1 enhances transcription. Accordingly, SCP1 may play a role in the regulation of gene expression, possibly by controlling the transition from initiation/capping to processive transcript elongation.
Evidence
3:
Inferred from Physical InteractionUniProtKB
Accurate and regulated transcription by RNA polymerase II requires the assembly of an initiation complex involving multiple protein-DNA and protein-protein interactions. A key event is binding of TFIID, a complex consisting of TBP and associated factors (TAFs) to the template DNA. The TAF subunits of TFIID carry out diverse functions critical for transcription, including specific contact with enhancer proteins and binding to core promoter DNA. However, the role of TAFs in RNA polymerase II-mediated transcription initiation and cross talk with other basal factors remains poorly characterized. Here, we report the specific interaction of TAFII250 with RAP74, an essential subunit of the basal transcription factor IIF. Using various in vitro binding assays we have mapped recognition interfaces between TAFII250 and RAP74. In vivo complementation of a temperature-sensitive TAFII250 cell line reveals that the RAP74 interaction is critical for cell viability. Because TFIIF is thought to be responsible for binding and recruiting RNA polymerase II, the ability of TAFII250 to interact selectively with RAP74 is likely to contribute a critical contact for the assembly of an active transcription complex.
Evidence
4:
Inferred from Physical InteractionUniProtKB
Proc. Natl. Acad. Sci. U.S.A. 92, 8195-8199 (1995)[PubMed:7667268]
Human transcription initiation factor TFIID is composed of the TATA-binding polypeptide (TBP) and at least 13 TBP-associated factors (TAFs) that collectively or individually are involved in activator-dependent transcription. To investigate protein-protein interactions involved in TFIID assembly and in TAF-mediated activator functions, we have cloned and expressed cDNAs encoding human TAFII80 and TAFII31. Coimmunoprecipitation assays showed that TAFII80 interacted with TAFII250, TAFII31, TAFII20, and TBP, but not with TAFII55. Similar assays showed that TAFII80 interacted with TFIIE alpha and with TFIIF alpha (RAP74) but not with TFIIB, TFIIE beta, or TFIIF beta (RAP30). Further studies with TAFII80 mutations revealed three distinct interaction domains which fall within regions conserved in human TAFII80, Drosophila TAFII60, and yeast TAFII60. The N terminus of TAFII80 (residues 1-100) interacts with both TAFII31 and TAFII20, while two C-terminal regions are involved, respectively, in interactions with TAFII250 and TFIIF alpha (RAP74) (residues 203-276) and with TBP and TFIIE alpha (residues 377-505). The interactions between TAFII80 and general factors TFIIE alpha and TFIIF alpha (RAP74) could be important for recruitment of GTFs during activator-dependent transcription. Because TAFs 80, 31, and 20 show sequence similarities to histones H4, H3, and H2B, as well as some parallel interactions, this subset of TAFs may form a related core structure within TFIID.
Interacting selectively and non-covalently with a activating transcription factor and also with the basal transcription machinery in order to increase the frequency, rate or extent of transcription. Cofactors generally do not bind DNA, but rather mediate protein-protein interactions between activating transcription factors and the basal transcription machinery.
A few general transcription factors, in particular TFIID and TFIIB, have been found to bind transcriptional activators. Here we show that the general transcription factor TFIIF is also a target for a transcriptional activator, namely serum response factor (SRF), which binds to the c-fos promoter. Using a yeast interaction assay, we find that SRF binds the RAP74 subunit of TFIIF and that SRF's transcriptional activation domain is the region involved in this binding. Further, RAP74's central charged cluster domain is required for binding to SRF's activation domain. Deletion of this domain impairs RAP74's ability to support SRF-activated transcription in vitro but has little effect on the protein's basal transcription activity or its ability to support SP1-activated transcription. The correlation of SRF-RAP74 binding with transcriptional activation suggests that RAP74 is a critical target for SRF-activated transcription.
Some TAF subunits of transcription factor TFIID play a pivotal role in transcriptional activation by mediating protein-protein interactions, whereas other TAFs direct promoter selectivity via protein-DNA recognition. Here, we report that purified recombinant TAFII250 is a protein serine kinase that selectively phosphotylates RAP74 but not other basal transcription factors or common phosphoacceptor proteins. The phosphorylation of RAP74 also occurs in the context of the complete TFIID complex. Deletion analysis revealed that TAFII250 contains two distinct kinase domains each capable of autophosphorylation. However, both the N- and C-terminal kinase domains of TAFII250 are required for efficient transphosphorylation of RAP74 on serine residues. These findings suggest that the targeted phosphorylation of RAP74 by TAFII250 may provide a mechanism for signaling between components within the initiation complex to regulate transcription.
Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus from a virus.
Evidence
1:
Inferred from Expression PatternUniProtKB
Insights into the host antiviral strategies as well as viral disease manifestations can be achieved through the elucidation of host- and virus-mediated transcriptional responses. An oligo-based microarray was employed to analyse mRNAs from rhabdomyosarcoma cells infected with the MS/7423/87 strain of enterovirus 71 (EV71) at 20 h post infection. Using Acuity software and LOWESS normalization, 152 genes were found to be downregulated while 39 were upregulated by greater than twofold. Altered transcripts include those encoding components of cytoskeleton, protein translation and modification; cellular transport proteins; protein degradation mediators; cell death mediators; mitochondrial-related and metabolism proteins; cellular receptors and signal transducers. Changes in expression profiles of 15 representative genes were authenticated by real-time reverse transcription polymerase chain reaction (RT-PCR), which also compared the transcriptional responses of cells infected with EV71 strain 5865/Sin/000009 isolated from a fatal case during the Singapore outbreak in 2000. Western blot analyses of APOB, CLU, DCAMKL1 and ODC1 proteins correlated protein and transcript levels. Two-dimensional proteomic maps highlighted differences in expression of cellular proteins (CCT5, CFL1, ENO1, HSPB1, PSMA2 and STMN1) following EV71 infection. Expression of several apoptosis-associated genes was modified, coinciding with apoptosis attenuation observed in poliovirus infection. Interestingly, doublecortin and CaM kinase-like 1 (DCAMKL1) involved in brain development, was highly expressed during infection. Thus, microarray, real-time RT-PCR and proteomic analyses can elucidate the global view of the numerous and complex cellular responses that contribute towards EV71 pathogenesis.
J. Biol. Chem. 274, 22387-22392 (1999)[PubMed:10428810]
The largest subunit of the human basal transcription factor TFIIFalpha (also called RAP74) was reported previously to be the target of some phospho/dephosphorylation process. We show that TFIIFalpha possesses a serine/threonine kinase activity, allowing an autophosphorylation of the two residues at position serine 385 and threonine 389. Mutation analysis strongly suggests that autophosphorylation of both sites regulates the transcription elongation process. Moreover we also evidence three additional phosphorylation sites located at positions 207-230, 271-283, and 335-344. These sites are phosphorylated by casein kinase II-like kinases and TAF(II)250, a component of TFIID.
Protein involved in the transfer of genetic information from DNA to messenger RNA (mRNA) by DNA-directed RNA polymerase. In the case of some RNA viruses, protein involved in the transfer of genetic information from RNA to messenger RNA (mRNA) by RNA-directed RNA polymerase.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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