Bibliographic Details
| Title: |
Two Steps in Maf1-dependent Repression of Transcription by RNA Polymerase III. |
| Authors: |
Desai, Neelam1, Jaehoon Lee1, Upadhya, Rajendra1, Yaya Chu1, Moir, Robyn D.1, Willis, Tan M.1 willis@aecom.yu.edu |
| Source: |
Journal of Biological Chemistry. 2/25/2005, Vol. 280 Issue 8, p6455-6462. 8p. 1 Graph. |
| Subject Terms: |
*SACCHAROMYCES cerevisiae, *GENETIC transcription, *CELLULAR signal transduction, *PHYSIOLOGICAL control systems, *RNA polymerases, *NUCLEIC acids |
| Abstract: |
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 Ill 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 Mail does not differentially sequester Brf1 or pol Ill under repressing conditions. The results suggest that Mail functions by a non-stoichiometric mechanism to repress pol III transcription. [ABSTRACT FROM AUTHOR] |
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| Database: |
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