Studying the Interplay between RNA Polymerase II and Nucleosome Dynamics

UNCP Author/Contributor (non-UNCP co-authors, if there are any, appear on document)
Ereny G. Gerges (Creator)
The University of North Carolina at Pembroke (UNCP )
Web Site:
Dr. Maria Santisteban

Abstract: In Saccharomyces cerevisiae, histone H2A.Z is coded by the HTZ1 gene. It is a highly conserved variant of histone H2A and has many reported roles in chromosome segregation and transcriptional regulation, among others. In yeast, this gene is not essential, unlike its homologues in other species where a deletion of this gene is lethal. We previously reported that Htz1 has a role in transcription elongation, but the mechanism of this is not yet understood. It has been shown that many elongation mutants exhibit a “cryptic” initiation phenotype, i.e. initiation of transcription by RNA pol II occurs inappropriately within the protein-coding regions of genes, rather than in the proximal promoter regions. Suppression of cryptic initiation requires a repressive chromatin structure. It is then expected that mutations in chromatin structure modifying factors, as well as elongation mutants, which may fail to reassemble nucleosomes in the wake of elongating RNA polymerase II (RNAPII), would display cryptic initiation phenotypes. We tested our strains for cryptic initiation phenotypes and have found that htz1? cells exhibit a mild cryptic initiation phenotype and htz1?RPB2-2SL has a strong cryptic initiation phenotype. A plausible explanation for these results is that the Rpb2-2 mutant polymerase is prone to cryptic initiation, and when nucleosome dynamics is altered in the absence of Htz1, the effect is exacerbated.

Additional Information

Honors Project
Esther G. Maynor Honors College
Language: English
Date: 2018
RNA Polymerase II, Nucleosome Dynamics, Histone H2A.Z, HTZ1 Gene, Chromosome Segregation, Transcription Elongation, Cryptic Initiation Phenotypes

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