Epigenetically-inherited centromere and neocentromere DNA replicates earliest in S-phase. Candida albicans

In order to address the replication timing of the centromeres in yeast Candida albicans, we have determined at high temporal and spatial resolution its genome-wide DNA replication timing profile. This was done by sorting S- and G1-phase cells by FACS and hybridizing DNA from both fractions onto genomic tiling arrays. Data was normalized, organized by chromosomal positition, and smoothed. Replication timing is inferred from the DNA copy number along the chromosome with data peaks corresponding to predicted origins of DNA replication. We observe that the centromeric loci coincide with replication origins that are the first to replicate on each chromosome. We further analyzed replication timing in strain 9929s, in which the centromere of chromosome 5 was deleted and a neocentromere has formed at a distant location. A replication origin, again the first to replicate, appeared at the site of neocentromere formation. We conclude that centromeres cause their own early and distinct DNA replication timing. Overall design: Four repeats of the wild type strain (SC5314) and two repeats of strain YJB9929s, S phase- vs G1 phase-cell DNA with different Cy dyes for each. The supplementary file 'GSE17963_final_data.txt' contains the fully processed replication timing data; its contents is described in 'GSE17963_readme.txt'.