TY - JOUR
T1 - The Tup1-Ssn6 general repressor is involved in repression of IME1 encoding a transcriptional activator of meiosis in Saccharomyces cerevisiae
AU - Mizuno, Takayuki
AU - Nakazawa, Nobushige
AU - Remgsamrarn, Panan
AU - Kunoh, Tatsuki
AU - Oshima, Yasuji
AU - Harashima, Satoshi
N1 - Funding Information:
Acknowledgements We thank M. Carlson for supplying S. cerevisiae strains and A. Sakai, Y. Kassir and G. Simchen for providing plasmids. We also thank Y. Kaneko and Y. Mukai of our laboratory for valuable comments. This study was partially supported by a Grant-in-Aid for Scientific Research (No. 06266212) to S. H. from the Ministry of Education, Science, Sports and Culture of Japan.
PY - 1998/4
Y1 - 1998/4
N2 - Ime1 plays a pivotal role in the initiation of meiosis in a/α diploid cells of Saccharomyces cerevisiae. In the absence of glucose and nitrogen, IME1 expression is greater in a/α cells than in either a or α cells and therefore only a/α, but not a/a or α/α cells are committed to sporulation. It is known that IME1 expression is positively regulated by Mck1, Rim1, Ime4 and the Swi-Snf complex but other factors may also be involved. In addition, Rme1 is assumed to repress IME1 expression. To provide more details of the repression of expression of IME1, we have isolated mutants in which the IME1p-PHO5 fusion gene integrated at the ura3 locus is expressed in α cells under nutritionally rich conditions. We found that mutations occurred in TUP1, SSN6, SIN4 and RGR1, among which TUP1 and SSN6 were identified for the first time as negative regulators of IME1 expression. Deletion of the Rme1-binding site from the IME1 promoter did not result in activation of the expression of IME1 under nutritionally rich conditions, suggesting that Rme1 does not function as a DNA-binding protein with the Tup1-Ssn6 repression complex. We also demonstrated that the 294-bp fragment from nucleotide position -914 to -621 and the 301-bp fragment from nucleotide position -1215 to -915 of the IME1 promoter region contain elements acting as URS and UAS in TUP1+ and tup1 mutant cells, respectively. These findings indicate that IME1 is negatively regulated by the Tup1-Ssn6 repressor complex through two distinct upstream regions in conjunction with unidentified DNA-binding proteins.
AB - Ime1 plays a pivotal role in the initiation of meiosis in a/α diploid cells of Saccharomyces cerevisiae. In the absence of glucose and nitrogen, IME1 expression is greater in a/α cells than in either a or α cells and therefore only a/α, but not a/a or α/α cells are committed to sporulation. It is known that IME1 expression is positively regulated by Mck1, Rim1, Ime4 and the Swi-Snf complex but other factors may also be involved. In addition, Rme1 is assumed to repress IME1 expression. To provide more details of the repression of expression of IME1, we have isolated mutants in which the IME1p-PHO5 fusion gene integrated at the ura3 locus is expressed in α cells under nutritionally rich conditions. We found that mutations occurred in TUP1, SSN6, SIN4 and RGR1, among which TUP1 and SSN6 were identified for the first time as negative regulators of IME1 expression. Deletion of the Rme1-binding site from the IME1 promoter did not result in activation of the expression of IME1 under nutritionally rich conditions, suggesting that Rme1 does not function as a DNA-binding protein with the Tup1-Ssn6 repression complex. We also demonstrated that the 294-bp fragment from nucleotide position -914 to -621 and the 301-bp fragment from nucleotide position -1215 to -915 of the IME1 promoter region contain elements acting as URS and UAS in TUP1+ and tup1 mutant cells, respectively. These findings indicate that IME1 is negatively regulated by the Tup1-Ssn6 repressor complex through two distinct upstream regions in conjunction with unidentified DNA-binding proteins.
KW - IME1
KW - Saccharomyces
KW - Sin4-Rgr1 repression
KW - Tup1-Ssn6 repression
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U2 - 10.1007/s002940050332
DO - 10.1007/s002940050332
M3 - Article
C2 - 9560430
AN - SCOPUS:0031898052
VL - 33
SP - 239
EP - 247
JO - Current Genetics
JF - Current Genetics
SN - 0172-8083
IS - 4
ER -