RNA polymerase II elongation factors Spt4p and Spt5p play roles in transcription elongation by RNA polymerase I and rRNA processing.
Previous investigations into the mechanisms that control RNA Polymerase (Pol) I transcription have primarily focused on the process of transcription initiation, thus little is known regarding postinitiation steps in the transcription cycle. Spt4p and Spt5p are conserved throughout eukaryotes, and they affect elongation by Pol II. We have found that these two proteins copurify with Pol I and associate with the rDNA in vivo. Disruption of the gene for Spt4p resulted in a modest decrease in growth and rRNA synthesis rates at the permissive temperature, 30 degrees C. Furthermore, biochemical and EM analyses showed clear defects in rRNA processing. These data suggest that Spt4p, Spt5p, and, potentially, other regulators of Pol I transcription elongation play important roles in coupling rRNA transcription to its processing and ribosome assembly.
Schneider
D A
DA
Department of Biological Chemistry, University of California, Irvine, CA 92697-1700, USA.
French
S L
SL
Osheim
Y N
YN
Bailey
A O
AO
Vu
L
L
Dodd
J
J
Yates
J R
JR
Beyer
A L
AL
Nomura
M
M
D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D008854:Microscopy, Electron; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012318:RNA Polymerase I / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism*
D002868:Chromosomal Proteins, Non-Histone; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; C080991:SPT4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035602:Transcriptional Elongation Factors; C069940:SPT5 transcriptional elongation factor; D012319:RNA Polymerase II; D012318:RNA Polymerase I