Silencing in yeast rDNA chromatin: reciprocal relationship in gene expression between RNA polymerase I and II
Francesco Cioci1, Loan Vu, Kristilyn Eliason
1Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.
Abstract:
About half of approximately 150 rRNA genes are transcriptionally active in Saccharomyces cerevisiae. Chromatin structures in the inactive, and not the active, copies were previously thought to silence both rRNA genes and reporter Pol II genes. Contrary to this belief, we found that silencing of reporters is much stronger in a mutant with approximately 25 rDNA copies, all of which are transcriptionally active. By integrating reporter gene mURA3 with an inactive rDNA copy missing the Pol I promoter, we found that mURA3 is not silenced in chromosomal rDNA repeats. Together with the demonstration of a requirement for active Pol I in silencing, these results show a reciprocal relationship in gene expression between Pol I and Pol II in rDNA.
Related Concept Videos
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
RNA Polymerase II Accessory Proteins
Eukaryotic Transcription Inhibitors
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Transcription Initiation
The promoters and enhancers and their accessory proteins allow tight regulation of...
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
RNA Polymerase II Accessory Proteins


