Investigating mechanisms of RNAi-dependent heterochromatin establishment in Schizosaccharomyces pombe
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Date
04/07/2020Author
Kapitonova, Ekaterina
Metadata
Abstract
Heterochromatin is a condensed conformation of eukaryotic DNA,
which plays an essential role in genome homeostasis. In depth
research across various species showed that RNA interference
(RNAi) is one of the pathways that is important for heterochromatin
formation. To date RNAi-driven heterochromatin assembly has been
extensively studied in the fission yeast Schizosaccharomyces
pombe. At centromeres in S. pombe, RNAi is required for
heterochromatin establishment and maintenance. Unlike
heterochromatin maintenance, RNAi-driven heterochromatin
establishment at the centromeres is not very well understood. The
interconnectedness between the RNAi and chromatin modification
pathways that are required to establish heterochromatin makes it
difficult to elucidate which pathway acts first. Recent studies also
showed that heterochromatin establishment requires additional
factors dispensable for maintenance. Thus exploring novel factors
required for the de novo heterochromatin formation can help us to
understand the order and the mechanism of heterochromatin
establishment. In this study I developed and tested two assays ⎯
plasmid-based and cross-based assays ⎯ designed to identify novel
establishment-specific factors genome-wide. While the plasmid
based assay proved unreliable, the cross-based establishment assay
was shown to effectively identify establishment-specific factors. It also provided new insights into heterochromatin establishment
dynamics.