Koç, AhmetWheeler, Linda J.Mathews, Christopher K.Merrill, Gary F.2017-06-192017-06-192003KOÇ, A., Linda, W., Chris, M., & Gary, M. (2003). Replication independent MCB gene induction and deoxyribonucleotide accumulation at G1 S in Saccharomyces cerevisiae . J Biol Chem, (278(11)), 9345–0.http://www.jbc.org/content/278/11/9345.full.pdfhttps://hdl.handle.net/11616/7111J Biol ChemIn Saccharomyces cerevisiae, many genes encoding enzymes involved in deoxyribonucleotide synthesis are expressed preferentially near the G1/S boundary of the cell cycle. The relationship between the induction of deoxyribonucleotide-synthesizing genes, deoxyribonucleoside triphosphate levels, and replication initiation was investigated using factor-synchronized wildtype yeast or dbf4 yeast that are temperature-sensitive for replication initiation. Neither the timing nor extent of gene induction was inhibited when factor-arrested dbf4 cells were released into medium containing the ribonucleotide reductase inhibitor hydroxyurea, which blocks replication fork progression, or were released at 37 °C, which blocks replication origin firing. Thus, the induction of deoxyribonucleotide-synthesizing genes at G1/S was fully independent of DNA chain elongation or initiation. Deoxyribonucleoside triphosphate levels increased severalfold at G1/S in wild-type cells and in dbf4 mutants incubated at the non-permissive temperature. Thus, deoxyribonucleoside triphosphate accumulation, like the induction of deoxyribonucleotide-synthesizing genes, was not dependent on replication initiation. Deoxyribonucleoside triphosphate accumulation at G1/S was suppressed in cells lacking Swi6, a transcription factor required for normal cell cycle regulation of deoxyribonucleotide-synthesizing genes. The results suggest that cells use gene induction at G1/S as a mechanism to pre-emptively, rather than reflexively, increase the synthesis of DNA precursors to meet the demand of the replication forks for deoxyribonucleotides.eninfo:eu-repo/semantics/openAccessArticle2781193450