title: Recombination and hydroxyurea inhibition of DNA synthesis in yeast meiosis.
abstract: Hydroxyurea (HU) inhibits the premeiotic DNA replication and the meiotic events that followed, namely readiness, recombination commitment, haploidisation, sporulation commitment and ascus formation. Short incubations with HU (2-4 hrs) during the premeiotic replication (i.e. starting between 3 and 6.5 hrs in sporulation medium) allow the resumption of the replication at a normal rate following the removal of the drug. The other meiotic events are similarly delayed by the approximate length of the treatment. In these experiments, intragenic recombination in ade2 reached a higher level than in the controls (x 1.3-2.0 in one pair of heteroalleles and x 3.0-4.0 in another pair). The recombination response to short HU treatments was not observed for a pair of heteroalleles in ade2 that normally shows a high level of meiotic recombination (750 per 10(6) cells), nor was the response observed in a pair of heteroalleles in lys2. HU treatments have almost no effect on sporulating cells from 8 hrs onwards. At 7-7.5 hrs the meiotic cells are very sensitive to the drug and even short treatments cause cell death and massive DNA degradation.
mesh_terms: D004261:DNA Replication / Q000187:drug effects*; D004171:Diploidy; D005787:Gene Frequency; D006918:Hydroxyurea / Q000494:pharmacology*; D008540:Meiosis; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013172:Spores, Fungal; D013997:Time Factors
chemical_list: D006918:Hydroxyurea