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The spatiotemporal program of replication in the genome of Lachancea kluyveri.

TitleThe spatiotemporal program of replication in the genome of Lachancea kluyveri.
Publication TypeJournal Article
Year of Publication2013
AuthorsAgier, N, Romano, OMaria, Touzain, F, Cosentino Lagomarsino, M, Fischer, G
JournalGenome Biol Evol
Date Published2013
KeywordsCentromere, Chromosomes, DNA Replication, GC Rich Sequence, Genome, Fungal, Replication Origin, S Phase, Saccharomyces cerevisiae, Telomere

We generated a genome-wide replication profile in the genome of Lachancea kluyveri and assessed the relationship between replication and base composition. This species diverged from Saccharomyces cerevisiae before the ancestral whole genome duplication. The genome comprises eight chromosomes among which a chromosomal arm of 1 Mb has a G + C-content much higher than the rest of the genome. We identified 252 active replication origins in L. kluyveri and found considerable divergence in origin location with S. cerevisiae and with Lachancea waltii. Although some global features of S. cerevisiae replication are conserved: Centromeres replicate early, whereas telomeres replicate late, we found that replication origins both in L. kluyveri and L. waltii do not behave as evolutionary fragile sites. In L. kluyveri, replication timing along chromosomes alternates between regions of early and late activating origins, except for the 1 Mb GC-rich chromosomal arm. This chromosomal arm contains an origin consensus motif different from other chromosomes and is replicated early during S-phase. We showed that precocious replication results from the specific absence of late firing origins in this chromosomal arm. In addition, we found a correlation between GC-content and distance from replication origins as well as a lack of replication-associated compositional skew between leading and lagging strands specifically in this GC-rich chromosomal arm. These findings suggest that the unusual base composition in the genome of L. kluyveri could be linked to replication.

Alternate JournalGenome Biol Evol
PubMed ID23355306
PubMed Central IDPMC3590768

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