The yeast regulator of transcription protein Rtr1 lacks an active site and phosphatase activity

Xiang, Kehui; Manley, James L.; Tong, Liang

doi:10.1038/ncomms1947

Cited by 42 publications

(57 citation statements)

References 36 publications

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“…Depleting fly RPAP2 did not give rise to snRNA misprocessing in our hands, suggesting that RPAP2 may fall into the group of factors we mentioned above or may not be critical in Drosophila. This latter would be consistent with observations that the fly CTD has a markedly distinct structure with very few serines at the seventh position within its heptad repeat, and the fly RPAP2 is significantly smaller than its human counterpart, possessing only the small zinc-finger domain recently found in the Kluyveromyces lactis RPAP2 crystal structure (Xiang et al 2012).…”

Section: Discussionsupporting

confidence: 91%

An RNAi screen identifies additional members of the Drosophila Integrator complex and a requirement for cyclin C/Cdk8 in snRNA 3′-end formation

Chen¹,

Ezzeddine²,

Waltenspiel

et al. 2012

RNA

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Formation of the 39 end of RNA polymerase II-transcribed snRNAs requires a poorly understood group of proteins called the Integrator complex. Here we used a fluorescence-based read-through reporter that expresses GFP in response to snRNA misprocessing and performed a genome-wide RNAi screen in Drosophila S2 cells to identify novel factors required for snRNA 39-end formation. In addition to the known Integrator complex members, we identified Asunder and CG4785 as additional Integrator subunits. Functional and biochemical experiments revealed that Asunder and CG4785 are additional core members of the Integrator complex. We also identified a conserved requirement in both fly and human snRNA 39-end processing for cyclin C and Cdk8 that is distinct from their function in the Mediator Cdk8 module. Moreover, we observed biochemical association between Integrator proteins and cyclin C/Cdk8, and that overexpression of a kinase-dead Cdk8 causes snRNA misprocessing. These data functionally define the Drosophila Integrator complex and demonstrate an additional function for cyclin C/Cdk8 unrelated to its function in Mediator.

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Section: Discussionsupporting

confidence: 91%

An RNAi screen identifies additional members of the Drosophila Integrator complex and a requirement for cyclin C/Cdk8 in snRNA 3′-end formation

Chen¹,

Ezzeddine²,

Waltenspiel

et al. 2012

RNA

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“…Thus, the Ssu72 phosphatase acts early in the transcription cycle, consistent with the initial identification of Ssu72 as a protein that interacts with TFIIB to affect start site selection (29). The significance of this result lies in two previous misconceptions: (i) that Rtr1 is the sole Ser(P) 5 phosphatase acting early in the transcription cycle and (ii) that Ssu72 dephosphorylates Ser(P) 5 only during transcription termination (21,34,35).…”

Section: Discussionsupporting

confidence: 60%

“…However, the role of Rtr1 as a CTD phosphatase has been challenged because its structure lacks an apparent catalytic site, and extensive efforts to demonstrate CTD phosphatase activity were unsuccessful (35). A more recent report described Rtr1 as a dual specificity phosphatase that dephosphorylates Tyr(P) 1 and Ser(P) 5 (36).…”

mentioning

confidence: 99%

The Ssu72 Phosphatase Mediates the RNA Polymerase II Initiation-Elongation Transition

Rosado-Lugo¹,

Hampsey

2014

Journal of Biological Chemistry

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Background: Ssu72 is a RNAPII CTD phosphatase; its function in the transcription cycle has not been established. Results: Ssu72 dephosphorylates Ser(P) 5 at the initiation-elongation transition and regulates Ser 2 phosphorylation status. Conclusion: Ssu72 functions at multiple stages of the RNAPII transcription cycle. Significance: Our results correct two previous misconceptions: (i) that Rtr1 is a Ser(P) 5 phosphatase and (ii) that Ssu72 dephosphorylates Ser(P) 5 only during transcription termination.

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“…RPAP2, the human homolog of Rtr1, has also been reported to possess Ser5-P phosphatase activity (Egloff et al 2012). However, the structure of Rtr1 was recently solved and did not reveal an apparent active site, and enzymatic assays with purified Rtr1 or RPAP2 and CTD substrates failed to detect activity (Xiang et al 2012). Thus, the role of Rtr1 in CTD dephosphorylation is currently unclear.…”

Section: Ctd Phosphatasesmentioning

confidence: 99%

The RNA polymerase II CTD coordinates transcription and RNA processing

2012

Self Cite

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The C-terminal domain (CTD) of the RNA polymerase II largest subunit consists of multiple heptad repeats (consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7), varying in number from 26 in yeast to 52 in vertebrates. The CTD functions to help couple transcription and processing of the nascent RNA and also plays roles in transcription elongation and termination. The CTD is subject to extensive post-translational modification, most notably phosphorylation, during the transcription cycle, which modulates its activities in the above processes. Therefore, understanding the nature of CTD modifications, including how they function and how they are regulated, is essential to understanding the mechanisms that control gene expression. While the significance of phosphorylation of Ser2 and Ser5 residues has been studied and appreciated for some time, several additional modifications have more recently been added to the CTD repertoire, and insight into their function has begun to emerge. Here, we review findings regarding modification and function of the CTD, highlighting the important role this unique domain plays in coordinating gene activity.Eukaryotes have three nuclear DNA-dependent RNA polymerases (RNAPs): RNAP I, RNAP II, and RNAP III. RNAP II, responsible for the synthesis of all mRNA as well as many noncoding RNAs (ncRNAs), consists of 12 polypeptides, of which Rpb1, which possesses the enzyme's catalytic activity, is the largest. Rpb1 also contains a C-terminal domain (CTD) composed of tandem heptad repeats that constitutes a unique feature of RNAP II and distinguishes it from all other polymerases. The CTD is conserved from fungi to humans, although the number of repeats and their deviation from the consensus vary, reflecting to a large degree the complexity of the organism. The CTD plays important roles at all steps of the transcription process, including enhancing or modulating the efficiency of all of the RNA processing reactions required for completion of synthesis of the mature RNA. The phosphorylation state of the CTD is critical in determining its activity.

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The yeast regulator of transcription protein Rtr1 lacks an active site and phosphatase activity

Cited by 42 publications

References 36 publications

An RNAi screen identifies additional members of the Drosophila Integrator complex and a requirement for cyclin C/Cdk8 in snRNA 3′-end formation

An RNAi screen identifies additional members of the Drosophila Integrator complex and a requirement for cyclin C/Cdk8 in snRNA 3′-end formation

The Ssu72 Phosphatase Mediates the RNA Polymerase II Initiation-Elongation Transition

The RNA polymerase II CTD coordinates transcription and RNA processing

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