TY - JOUR
T1 - Functional interaction between TFIIB and the Rpb9 (Ssu73) subunit of RNA polymerase II in Saccharomyces cerevisiae
AU - Sun, Zu Wen
AU - Tessmer, Amy
AU - Hampsey, Michael
N1 - Funding Information:
We are grateful to David Gross for valuable discussions and critical comments on the manuscript. We thank Rolf Furter, Lynn Henry, Roger Kornberg and David Drubin for plasmids carrying the RPB9, TFG2 and TFG3/ANC1 genes. This work was supported by research grants from the American Cancer Society (NP-842) and the National Institutes of Health (GM-39484).
PY - 1996
Y1 - 1996
N2 - Recessive mutations in the SSU71, SSU72 and SSU73 genes of Saccharomyces cerevisiae were identified as either suppressors or enhancers of a TFIIB defect (sua7-1) that confers both a cold-sensitive growth phenotype and a downstream shift in transcription start site selection. The SSU71 (TFG1) gene encodes the largest subunit of TFIIF and SSU72 encodes a novel protein that is essential for cell viability. Here we report that SSU73 is identical to RPB9 the gene encoding the 14.2 kDa subunit of RNA polymerase II. The ssu73-1 suppressor compensates for both the growth defect and the downstream shift in start site selection associated with sua7-1. These effects are similar to those of the ssu71-1 suppressor and distinct from the ssu72-1 enhancer. The ssu73-1 allele was retrieved and sequenced, revealing a nonsense mutation at codon 107. Consequently, ssu73-1 encodes a truncated form of Rpb9 lacking the C-terminal 16 amino acids. This Rpb9 derivative retains at least partial function since the ssu73-1 mutant exhibits none of the growth defects associated with rpb9 null mutants. However, in a SUA7+ background, ssu73-1 confers the same upstream shift at ADH1 as an rpb9 null allele. This suggests that the C-terminus of Rpb9 functions in start site selection and demonstrates that the previously observed effects of rpb9 mutations on start site selection are not necessarily due to complete loss of function. These results establish a functional interaction between TFIIB and the Rpb9 subunit of RNA polymerase II and suggest that these two components of the preinitiation complex interact during transcription start site selection.
AB - Recessive mutations in the SSU71, SSU72 and SSU73 genes of Saccharomyces cerevisiae were identified as either suppressors or enhancers of a TFIIB defect (sua7-1) that confers both a cold-sensitive growth phenotype and a downstream shift in transcription start site selection. The SSU71 (TFG1) gene encodes the largest subunit of TFIIF and SSU72 encodes a novel protein that is essential for cell viability. Here we report that SSU73 is identical to RPB9 the gene encoding the 14.2 kDa subunit of RNA polymerase II. The ssu73-1 suppressor compensates for both the growth defect and the downstream shift in start site selection associated with sua7-1. These effects are similar to those of the ssu71-1 suppressor and distinct from the ssu72-1 enhancer. The ssu73-1 allele was retrieved and sequenced, revealing a nonsense mutation at codon 107. Consequently, ssu73-1 encodes a truncated form of Rpb9 lacking the C-terminal 16 amino acids. This Rpb9 derivative retains at least partial function since the ssu73-1 mutant exhibits none of the growth defects associated with rpb9 null mutants. However, in a SUA7+ background, ssu73-1 confers the same upstream shift at ADH1 as an rpb9 null allele. This suggests that the C-terminus of Rpb9 functions in start site selection and demonstrates that the previously observed effects of rpb9 mutations on start site selection are not necessarily due to complete loss of function. These results establish a functional interaction between TFIIB and the Rpb9 subunit of RNA polymerase II and suggest that these two components of the preinitiation complex interact during transcription start site selection.
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U2 - 10.1093/nar/24.13.2560
DO - 10.1093/nar/24.13.2560
M3 - Article
C2 - 8692696
AN - SCOPUS:0029989059
SN - 0305-1048
VL - 24
SP - 2560
EP - 2566
JO - Nucleic acids research
JF - Nucleic acids research
IS - 13
ER -