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Ribosomal DNA replication time coordinates completion of genome replication and anaphase in yeast

ABSTRACT: Ribosomal DNA (rDNA) is organized as large arrays of tandem repeats that vary in copy number from a few dozen to hundreds. In the budding yeast Saccharomyces cerevisiae, each rDNA repeat includes a potential origin of replication. Previous work has led to the model that the rDNA replication origins compete for limiting replication initiation factors with origins in the rest of the genome, suggesting that reduction in rDNA copy number would reduce competition for these limiting factors and therefore promote origin usage in the rest of the genome. To test this hypothesis, we compared genome-wide replication in strains with either wild type rDNA copy number of ~180 (“180 rDNA”) or just ~35 copies (“35 rDNA”) by performing dense-to-light isotope transfer experiments to physically separate replicated, hybrid-density (HL or heavy-light) DNA from unreplicated, HH (heavy-heavy) DNA in cell samples collected at different times in S phase. Contrary to our expectations, we find that although there are no apparent differences in non-rDNA origin activity between the two strains, the 35 rDNA strain shows a genome-wide delay in progression through S phase compared to the 180 rDNA strain.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE205068 | GEO | 2023/02/17

REPOSITORIES: GEO

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