Investigating a possible interplay between Hho1p and Hmo1p during stationary phase in Saccharomyces cerevisiae.

Abstract

Chromatin organisation during the stationary phase in Saccharomyces cerevisiae plays a vital role in genome stability and transcriptional regulation. The aim of this research was to investigate any potential interaction between Hho1p and Hmo1p during the stationary phase in Saccharomyces cerevisiae. The hypothesis was that Hho1p and Hmo1p interact to maintain chromatin structure and regulate transcription during stationary phase in Saccharomyces cerevisiae. To test this hypothesis, single and double HMO1 and HHO1 gene deletion mutants were constructed, and their phenotypes were compared. The results show that the single gene deletion mutants of hho1Δ mutant and hmo1Δ mutant have distinct but partially overlapping phenotypes during the exponential and stationary phase. However, the hho1Δ hmo1Δ double mutant exhibited the strongest phenotypic effects compared to the wild type and both single mutants in exponential and stationary phase. ChIPseq data also revealed an overlap in the sites occupied by both Hmo1p and Hho1p in exponential and stationary phase cells. These data suggest a potential interplay between Hho1p and Hmo1p whereby they may act in a co-ordinated and interactive manner during both exponential and stationary phase, with growth phase specific phenotypic influence and effect. The findings from this research contribute to a greater understanding of the roles of Hho1p and Hmo1p and the interactions between both proteins at different stages of the of the yeast cell growth cycle. This research highlights the importance of Hmo1p and Hho1p in different stages of the yeast cell growth cycle and paves the way for future work comparing the hho1Δ hmo1Δ double mutant transcription profile to wt and the single mutants to identify the unique and shared roles of the Hmo1p and Hho1p proteins upon global gene transcription and cell function.