Nhp6A and Nhp6B are HMG1-like proteins required for the growth of S. cerevisiae at elevated temperatures. We show that the conditional lethality of an nhp6 strain results from defective transcription of SNR6 (U6 snRNA) by RNA polymerase III. Overexpression of U6 snRNA or Brf1, a limiting component of TFIIIB, and an activating mutation (PCF1-1) in TFIIIC were each found to suppress the nhp6 growth defect. Additionally, U6 snRNA levels, which are reduced over 10-fold in nhp6 cells at 37 degrees C, were restored by Brf1 overexpression and by PCF1-1. Nhp6A protein specifically enhanced TFIIIC-dependent, but not TATA box-dependent, SNR6 transcription in vitro by facilitating TFIIIC binding to the SNR6 promoter. Thus, Nhp6 has a direct role in transcription complex assembly at SNR6.

• PMID: 11239460
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Reference Type

Journal Article | Research Support, U.S. Gov't, P.H.S.

Authors

Kruppa M, Moir RD, Kolodrubetz D, Willis IM

Primary Lit For

SNR6 | NHP6A | General transcription factor TFIIIB complex | General transcription factor TFIIIC complex | DNA-directed RNA polymerase III complex

Additional Lit For

BRF1 | TFC4

Review For