Pcf11 is a termination factor in Drosophila that dismantles the elongation complex by bridging the CTD of RNA polymerase II to the nascent transcript.
The mechanism by which Pol II terminates transcription in metazoans is not understood. We show that Pcf11 is directly involved in termination in Drosophila. dPcf11 is concentrated at the 3' end of the hsp70 gene in cells, and depletion of dPcf11 with RNAi causes Pol II to readthrough the normal region of termination. dPcf11 also localizes to most transcribed loci on polytene chromosomes. Biochemical analysis reveals that dPcf11 dismantles elongation complexes by a CTD-dependent but nucleotide-independent mechanism and that dPcf11 forms a bridge between the CTD and RNA. This bridge appears to be crucial because an anti-CTD antibody, which also dismantles the elongation complex, is found to bridge the CTD to RNA. dPcf11 was observed to inhibit transcription at low, but not high, nucleotide levels, suggesting that dPcf11 dismantles paused elongation complexes. These results provide a biochemical basis for the dependency of termination on pausing and the CTD in metazoans.
Zhang
Zhiqiang
Z
Department of Biochemistry and Molecular Biology, Center for Gene Regulation, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Gilmour
David S
DS
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002875:Chromosomes / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D034622:RNA Interference; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism*; D039221:mRNA Cleavage and Polyadenylation Factors / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins; D046911:Macromolecular Substances; D012333:RNA, Messenger; D035602:Transcriptional Elongation Factors; D039221:mRNA Cleavage and Polyadenylation Factors; D000255:Adenosine Triphosphate; D012319:RNA Polymerase II