The Paf1 complex physically and functionally associates with transcription elongation factors in vivo.
We are using biochemical and genetic approaches to study Rtf1 and the Spt4-Spt5 complex, which independently have been implicated in transcription elongation by RNA polymerase II. Here, we report a remarkable convergence of these studies. First, we purified Rtf1 and its associated yeast proteins. Combining this approach with genetic analysis, we show that Rtf1 and Leo1, a protein of unknown function, are members of the RNA polymerase II-associated Paf1 complex. Further analysis revealed allele-specific genetic interactions between Paf1 complex members, Spt4-Spt5, and Spt16-Pob3, the yeast counterpart of the human elongation factor FACT. In addition, we independently isolated paf1 and leo1 mutations in an unbiased genetic screen for suppressors of a cold-sensitive spt5 mutation. These genetic interactions are supported by physical interactions between the Paf1 complex, Spt4-Spt5 and Spt16-Pob3. Finally, we found that defects in the Paf1 complex cause sensitivity to 6-azauracil and diminished PUR5 induction, properties frequently associated with impaired transcription elongation. Taken together, these data suggest that the Paf1 complex functions during the elongation phase of transcription in conjunction with Spt4-Spt5 and Spt16-Pob3.
Squazzo
Sharon L
SL
Department of MCD Biology, University of California, Santa Cruz, CA 95064, USA.
Costa
Patrick J
PJ
Lindstrom
Derek L
DL
Kumer
Kathryn E
KE
Simic
Rajna
R
Jennings
Jennifer L
JL
Link
Andrew J
AJ
Arndt
Karen M
KM
Hartzog
Grant A
GA
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D012319:RNA Polymerase II / Q000378:metabolism* / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D035602:Transcriptional Elongation Factors
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D009687:Nuclear Proteins; C097698:PAF1 protein, S cerevisiae; C106768:POB3 protein, S cerevisiae; C107273:RTF1 protein, S cerevisiae; C071238:SPT16 protein, S cerevisiae; C080991:SPT4 protein, S cerevisiae; C489489:SUPT16H protein, human; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C069940:SPT5 transcriptional elongation factor; D012319:RNA Polymerase II