Two steps in Maf1-dependent repression of transcription by RNA polymerase III.

Journal Article (Journal Article)

In Saccharomyces cerevisiae, Maf1 is essential for mediating the repression of transcription by RNA polymerase (pol) III in response to diverse cellular conditions. These conditions activate distinct signaling pathways that converge at or above Maf1. Thus, Maf1-dependent repression is thought to involve a common set of downstream inhibitory effects on the pol III machinery. Here we provide support for this view and define two steps in Maf1-dependent transcriptional repression. We show that chlorpromazine (CPZ)-induced repression of pol III transcription is achieved by inhibiting de novo assembly of transcription factor (TF) IIIB onto DNA as well as the recruitment of pol III to preassembled TFIIIB.DNA complexes. Additionally Brf1 was identified as a target of repression in extracts of CPZ-treated cells. Maf1-Brf1 and Maf1-pol III interactions were implicated in the inhibition of TFIIIB.DNA complex assembly and polymerase recruitment by recombinant Maf1. Co-immunoprecipitation experiments confirmed these interactions in yeast extracts and demonstrated that Maf1 does not differentially sequester Brf1 or pol III under repressing conditions. The results suggest that Maf1 functions by a non-stoichiometric mechanism to repress pol III transcription.

Full Text

Duke Authors

Cited Authors

  • Desai, N; Lee, J; Upadhya, R; Chu, Y; Moir, RD; Willis, IM

Published Date

  • February 25, 2005

Published In

Volume / Issue

  • 280 / 8

Start / End Page

  • 6455 - 6462

PubMed ID

  • 15590667

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M412375200

Language

  • eng

Conference Location

  • United States