chengbo20035@yahoo.com.cn
Mentor: David Price, Ph.D.
Lab Phone: 335-6742

Mechanisms of P-TEFb-mediated RNA polymerase II elongation control

The positive transcription elongation factor, P-TEFb, controls the fraction of initiated RNA polymerase II molecules that enter into the productive mode of elongation necessary to generate mRNAs. The overall goal of my project is to advance our understanding of the mechanism of this transition into productive elongation by using a combination of biochemical and molecular techniques. I optimized a defined in vitro transcription system and compared results obtained with it to those obtained with a crude system. I found that controlling the function of TFIIF is a key aspect of RNA polymerase II elongation control. Before P-TEFb function early elongation complexes under the control of negative factors are completely unresponsive to the robust elongation stimulatory activity of TFIIF. P-TEFb-mediated phosphorylation events reverse the negative effect of DSIF and NELF and simultaneously facilitate the action of TFIIF. Once this transition has occurred, the productive elongation complexes are completely resistant to negative elongation factors. Meanwhile, I have set up an elongation complex-electrophoretic mobility shift assay (EC-EMSA) to examine the dynamic association of various elongation factors with elongation complexes.

Cheng B, Li T, Rahl PB, Adamson TE, Loudas NB, Guo J, Varzavand K, Cooper JJ, Hu X, Gnatt A, Young RA, Price DH. Functional association of Gdown1 with RNA polymerase II poised on human genes. Mol Cell. 2012 Jan 13;45(1):38-50. PubMed PMID: 22244331; PubMed Central PMCID: PMC3259526.

Cheng B, Price DH. Isolation and functional analysis of RNA polymerase II elongation complexes. Methods. 2009 Aug;48(4):346-52. Epub 2009 May 4. PubMed PMID: 19409997; PubMed Central PMCID: PMC2754188.

Cheng B, Price DH. Analysis of factor interactions with RNA polymerase II elongation complexes using a new electrophoretic mobility shift assay. Nucleic Acids Res. 2008 Nov;36(20):e135. Epub 2008 Oct 1. PubMed PMID: 18832375; PubMed Central PMCID: PMC2582608.

Cheng B, Price DH. Properties of RNA polymerase II elongation complexes before and after the P-TEFb-mediated transition into productive elongation. J Biol Chem. 2007 Jul 27;282(30):21901-12. Epub 2007 Jun 4. PubMed PMID: 17548348.

Abstracts

Cheng, B. and Price, D.H. Analysis of the functional association of DSIF and other elongation factors with the RNA Pol II elongation complex. Keystone Symposia Conference on Regulation of Eukaryotic Transcription, CO, Feb. 3rd-8th, 2008.

Cheng, B. and Price, D.H. Properties of RNA Polymerase II elongation complexes before and after the P-TEFb-mediated transition into productive elongation. Cold Spring Harbor Meeting on Mechanisms of Eukaryotic Transcription, NY, Aug. 29th-Sep. 2nd, 2007.

Cheng, B. and Price, D.H. Dissection of the functional mechanisms of P-TEFb in RNA Polymerase II elongation control. 13th Biennial Meeting on Post-Initiation Activities of RNA Polymerases, VA, Nov. 2nd-5th, 2006.

Cheng, B. and Price, D.H. Analysis of RNA Polymerase II elongation control using a defined in vitro system. Midwest Meeting on Chromatin, Transcription and Nuclear Dynamics, IA, Jul. 14th-16th, 2006.

Cheng, B., Li, Qintong, Price, J.P. and Price, D.H. Analysis of control of P-TEFb function using a defined in vitro transcription system. Keystone Symposia Conference on Regulation of Eukaryotic Transcription: From Chromatin to mRNA, NM, Apr. 21st-26th, 2006.