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Mediator complex association with constitutively transcribed genes in yeast
被引:53
作者:
Ansari, Suraiya A.
[1
]
He, Qiye
[2
]
Morse, Randall H.
[1
,2
]
机构:
[1] New York State Dept Hlth, Wadsworth Ctr, Mol Genet Lab, Albany, NY 12201 USA
[2] SUNY Albany, Sch Publ Hlth, Dept Biomed Sci, Albany, NY 12201 USA
来源:
基金:
美国国家科学基金会;
关键词:
Rap1;
transcription;
RNA-POLYMERASE-II;
GENOME-WIDE ANALYSIS;
IN-VIVO TARGET;
TRANSCRIPTIONAL ACTIVATION;
SACCHAROMYCES-CEREVISIAE;
INDEPENDENT RECRUITMENT;
BINDING PROTEIN;
HEAT-SHOCK;
HOLOENZYME;
PROMOTER;
D O I:
10.1073/pnas.0905103106
中图分类号:
O [数理科学和化学];
P [天文学、地球科学];
Q [生物科学];
N [自然科学总论];
学科分类号:
07 ;
0710 ;
09 ;
摘要:
Mediator is a large, multisubunit complex that is essential for transcription of mRNA by RNA Pol II in eukaryotes and is believed to bridge transcriptional activators and the general transcription machinery. However, several recent studies suggest that the requirement for Mediator during transcriptional activation is not universal, but rather activator dependent, and may be indirect for some genes. Here we have investigated Mediator association with several constitutively transcribed genes in yeast by comparing a yeast strain that harbors a temperature-sensitive mutation in an essential Mediator subunit, Srb4, with its wild-type (WT) counterpart. We find modest association of Mediator with constitutively active genes and show that this association is strongly decreased in srb4 ts yeast, whereas association with a nontranscribed region or repressed gene promoters is lower and unaffected in the mutant yeast. The tail module of Mediator remains associated with ribosomal protein (RP) gene promoters in srb4 ts yeast, while subunits from the head and middle modules are lost. Tail module association at Rap1-dependent gene promoters is lost in rap1 ts yeast, indicating that Rap1 is required for Mediator recruitment at these gene promoters and that its recruitment occurs via the tail module. Pol II association is also rapidly and severely affected in srb4 ts yeast, indicating that Mediator is directly required for pol II association at constitutively transcribed genes. Our results are consistent with Mediator functioning as a general transcription factor in yeast.
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页码:16734 / 16739
页数:6
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