Functional Interactions of the RNA Polymerase II-interacting Proteins Gdown1 and TFIIF

Melissa A Mullen Davis; Jiannan Guo; David H Price; Donal S Luse

doi:10.1074/jbc.M113.544395

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Functional Interactions of the RNA Polymerase II-interacting Proteins Gdown1 and TFIIF

Journal article

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Functional Interactions of the RNA Polymerase II-interacting Proteins Gdown1 and TFIIF

Melissa A Mullen Davis, Jiannan Guo, David H Price and Donal S Luse

The Journal of biological chemistry, Vol.289(16), pp.11143-11152

04/18/2014

DOI: 10.1074/jbc.M113.544395

PMCID: PMC4036253

PMID: 24596085

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Abstract

Background: Gdown1 modulates pausing in early elongation but also blocks binding of the essential initiation factor TFIIF to pol II. Results: TFIIF can compete successfully with Gdown1 to support preinitiation complex assembly. Conclusion: Gdown1 cannot functionally interact with already formed preinitiation complexes. Significance: Pathways exist allowing Gdown1 to enter the transcription complex early in elongation, thus allowing Gdown1 to affect pausing. Gdown1, the substoichiometric 13th subunit of RNA polymerase II (pol II), has an important role in pausing during the initial stage of transcript elongation. However, Gdown1 quantitatively displaces the essential initiation factor TFIIF from free pol II and elongating pol II. Thus, it is not clear how or even if pol II can initiate in the presence of Gdown1. Using an in vitro transcription system with purified factors and pol II lacking Gdown1, we found that although Gdown1 is strongly inhibitory to transcription when prebound to pol II, a fraction of complexes do remain active. Surprisingly, when Gdown1 is added to complete preinitiation complexes (PICs), it does not inhibit initiation or functionally associate with the PICs. Gdown1 does associate with pol II during the early stage of transcript elongation but this association is competitive with TFIIF. By phosphorylating TFIIF, PICs can be assembled that do not retain TFIIF. Gdown1 also fails to functionally associate with these TFIIF-less PICs, but once polymerase enters transcript elongation, complexes lacking TFIIF quantitatively bind Gdown1. Our results provide a partial resolution of the paradox of the competition between Gdown1 and TFIIF for association with pol II. Although Gdown1 completely displaces TFIIF from free pol II and elongation complexes, Gdown1 does not functionally associate with the PIC. Gdown1 can enter the transcription complex immediately after initiation. Modification of TFIIF provides one pathway through which efficient Gdown1 loading can occur early in elongation, allowing downstream pausing to be regulated.

Gene Regulation

POLR2M

General Transcription Factors

Transcription

TFIIF

Gdown1

Transcription Initiation Factors

Preinitiation Complex

RNA Polymerase II

GRINL1A

Transcription Elongation Factors

Details

Title: Subtitle: Functional Interactions of the RNA Polymerase II-interacting Proteins Gdown1 and TFIIF
Creators: Melissa A Mullen Davis - From the
Jiannan Guo - the
David H Price - the
Donal S Luse - From the
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.289(16), pp.11143-11152
DOI: 10.1074/jbc.M113.544395
PMID: 24596085
PMCID: PMC4036253
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Publisher: American Society for Biochemistry and Molecular Biology; 9650 Rockville Pike, Bethesda, MD 20814, U.S.A
Grant note: GM35500 / National Institutes of Health
Alternative title: TFIIF Competes with Gdown1 within Some Pol II Complexes
Language: English
Date published: 04/18/2014
Academic Unit: Biochemistry and Molecular Biology
Record Identifier: 9984025248902771

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