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RNAP‐II transcribes two small RNAs at the promoter and terminator regions of the RNAP‐I gene in Saccharomyces cerevisiae
Author(s) -
Mayán Maria D.
Publication year - 2013
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.2938
Subject(s) - biology , genetics , rna polymerase , transcription (linguistics) , rna polymerase iii , saccharomyces cerevisiae , promoter , gene , rna polymerase ii , chromatin , rna , ribosomal rna , gene expression , linguistics , philosophy
Three RNA polymerases coexist in the ribosomal DNA of Saccharomyces cerevisiae . RNAP‐I transcribes the 35S rRNA, RNAP‐III transcribes the 5S rRNA and RNAP‐II is found in both intergenic non‐coding regions. Previously, we demonstrated that RNAP‐II molecules bound to the intergenic non‐coding regions (IGS) of the ribosomal locus are mainly found in a stalled conformation, and the stalled polymerase mediates chromatin interactions, which isolate RNAP‐I from the RNAP‐III transcriptional domain. Besides, RNAP‐II transcribes both IGS regions at low levels, using different cryptic promoters. This report demonstrates that RNAP‐II also transcribes two sequences located in the 5′‐ and 3′‐ends of the 35S rRNA gene that overlap with the sequences of the 35S rRNA precursor transcribed by RNAP‐I. The sequence located at the promoter region of RNAP‐I, called the p‐RNA transcript, binds to the transcription termination‐related protein, Reb1p, while the T‐RNA sequence, located in the termination sites of RNAP‐I gene, contains the stem–loop recognized by Rtn1p, which is necessary for proper termination of RNAP‐I. Because of their location, these small RNAs may play a key role in the initiation and termination of RNAP‐I transcription. To correctly synthesize proteins, eukaryotic cells may retain a mechanism that connects the three main polymerases. This report suggests that cryptic transcription by RNAP‐II may be required for normal transcription by RNAP‐I in the ribosomal locus of S. cerevisiae . Copyright © 2012 John Wiley & Sons, Ltd.