S phase and HU profiles in wild-type and mutant cells

Total S phase was measured for wild-type cells undergoing meiS and mitS. Early replication origins were mapped in mitS in wild-type cells, and in meiS for wild-type, sml1 delete, rec8 delete and spo11 delete cells. Comparative genome hybridization was used to measure the kinetics and final extent of DNA replication in wild-type and mutant cells. First, S phase profiles were produced from wild-type cells undergoing pre-mitotic S phase (mitS) and pre-meiotic S phase (meiS) to measure the kinetics of DNA replication in the two S phases. For these experiments, a pool of samples collected throught out all of S phase were labeled and hybridized to a microarray together with a control G1 DNA sample. Second, early replication origins were mapped by exposing cells to levels of HU that strongly reduced DNA replication. Early replication was compared for wild-type cells in mitS to wild-type, sml1, rec8 and spo11 delete strain undergoing meiS. In these experiment, samples were collected after 4 hours exposure to HU. Total genomic DNA was isolated, labeled and hybridized to a microarray together with a control G1 DNA sample. A control G1 vs. G1 sample was prepared to measure the level of noise inherent in the CGH technique.