Evidence that Spt4, Spt5, and Spt6 control transcription elongation by RNA polymerase II in Saccharomyces cerevisiae.

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121

作者：

GA Hartzog，T Wada，H Handa，F Winston

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摘要：

Previous characterization of the Spt4, Spt5, and Spt6 proteins suggested that these proteins act as transcription factors that modify chromatin structure. In this work, we report new genetic and biochemical studies of Spt4, Spt5, and Spt6 that reveal a role for these factors in transcription elongation. We have isolated conditional mutations in that can be suppressed in an allele-specific manner by mutations in the two largest subunits of RNA polymerase II (Pol II). Strikingly, one of these RNA Pol II mutants is defective for transcription elongation and the others cause phenotypes consistent with an elongation defect. In addition, we show that and mutants themselves have phenotypes suggesting defects in transcription elongation in vivo. Consistent with these findings, we show that Spt5 is physically associated with RNA Pol II in vivo, and have identified a region of sequence similarity between Spt5 and NusG, an transcription elongation factor that binds directly to RNA polymerase. Finally, we show that Spt4 and Spt5 are tightly associated in a complex that does not contain Spt6. These results, taken together with the biochemical identification of a human Spt4–Spt5 complex as a transcription elongation factor (), provide strong evidence that these factors are important for transcription elongation in vivo.

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关键词：

Saccharomyces cerevisiae Transcription Factors Transcriptional Elongation Factors RNA Polymerase II Transcription Factors, General Saccharomyces cerevisiae Proteins Nuclear Proteins Chromosomal Proteins, Non-Histone Protein Binding Sequence Homology, Amino Acid