description
Transcription elongation by RNA polymerase II (RNAPII) is controlled by a number of trans-acting transcription elongation factors as well as by cis-acting elements. Transcription elongation is a rate-limiting step for proper mRNA production in which the phosphorylation of Pol II CTD is a crucial biochemical event. The role of CTD phosphorylation in transcription by Pol II is greatly impaired by protein kinase inhibitors such as 5,6-dichloro-1- ribofuranosylbenzimidazole (DRB), which block CTD phosphorylation and induce arrest of elongating Pol II. DRB-sensitive activation Pol II CTD during elongation has enabled the isolation of two sets of factors -Negative Elongation Factors (NELF) and DRB sensitivity inducing factor (DSIF). P-Tefb is a DRB-sensitive, cyclin-dependent CTD kinase composed of Cdk9 that carries out Serine-2 phosphorylation of Pol II CTD during elongation.The mechanism by which DSIF, NELF and P-TEFb act together in Pol II-regulated elongation is yet to be fully understood. Various biochemical evidences point to a model in which DSIF and NELF negatively regulate elongation through interactions with polymerase containing a hypophosphorylated CTD. Subsequent phosphorylation of the Pol II CTD by P-Tefb might promote elongation by inhibiting interactions of DSIF and NELF with the elongation complex

external resources
NCBI:1269683
REACTOME:R-HSA-113418
PUBMED:11940650
PUBMED:10916156

genes
CCNH , CDK7 , ERCC2 , ERCC3 , GTF2F1 , GTF2F2 , GTF2H1 , GTF2H2 , GTF2H3 , GTF2H4 , MNAT1 , NCBP1 , POLR2A , POLR2B , POLR2C , POLR2D , POLR2E , POLR2F , POLR2G , POLR2H , POLR2I , POLR2J , POLR2K , POLR2L , SUPT4H1 , SUPT5H , NELFA , NELFE , CTDP1 , NCBP2 , NELFB , NELFCD , GTF2H5 , MIR943 , MIR1236 ,