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Cell Cycle. 2003 May-Jun;2(3):181-4.

Direct regulation of RNA polymerase III transcription by RB, p53 and c-Myc.

Author information

1
Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.

Abstract

The synthesis of tRNA and 5S rRNA by RNA polymerase (pol) III is cell cycle regulated in higher organisms. Overexpression of pol III products is a general feature of transformed cells. These observations may be explained by the fact that a pol III-specific transcription factor, TFIIIB, is strongly regulated by the tumor suppressors RB and p53, as well as the proto-oncogene product c-Myc. RB and p53 repress TFIIIB, but this restraint can be lost in tumors through a variety of mechanisms. In contrast, c-Myc binds and activates TFIIIB, causing potent induction of pol III transcription. Using chromatin immunoprecipitation and RNA interference, we show that c-Myc interacts with tRNA and 5S rRNA genes in transformed cervical cells, stimulating their expression. Availability of pol III products may be an important determinant of a cell's capacity to grow. The ability to regulate pol III output may therefore be integral to the growth control functions of RB, p53 and c-Myc.

PMID:
12734418
[Indexed for MEDLINE]

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