Koç, AhmetMathews, Christopher K.Wheeler, Linda J.Gross, Michael K.Merrill, Gary F.2017-06-192017-06-192006KOÇ, A., Chris, M., Linda, W., Micheal, G., & Gary, M. (2006). Thioredoxin is required for deoxyribonucleotide pool maintenance during S phase . J Biol Chem, (281(22)), 15058–0.http://www.jbc.org/content/281/22/15058.full.pdfhttps://hdl.handle.net/11616/7103J Biol ChemThioredoxin was initially identified by its ability to serve as an electron donor for ribonucleotide reductase in vitro. Whether it serves a similar function in vivo is unclear. In Saccharomyces cerevisiae, it was previously shown that trx1 trx2 mutants lacking the two genes for cytosolic thioredoxin have a slower growth rate because of a longer S phase, but the basis for S phase elongation was not identified. The hypothesis that S phase protraction was due to inefficient dNTP synthesis was investigated by measuring dNTP levels in asynchronous and synchronized wild-type and trx1 trx2 yeast. In contrast to wild-type cells, trx1 trx2 cells were unable to accumulate or maintain high levels of dNTPs when -factor- or cdc15-arrested cells were allowed to reenter the cell cycle. At 80 min after release, when the fraction of cells in S phase was maximal, the dNTP pools in trx1 trx2 cells were 60% that of wild-type cells. The data suggest that, in the absence of thioredoxin, cells cannot support the high rate of dNTP synthesis required for efficient DNA synthesis during S phase. The results constitute in vivo evidence for thioredoxin being a physiologically relevant electron donor for ribonucleotide reductase during DNA precursor synthesis.eninfo:eu-repo/semantics/openAccessArticle28122150580