Nature of abortive transformation in Saccharomyces cerevisiae
1995
Yap, W.Y. | Schiestl, R.H. (Harvard School of Public Health, Boston (USA). Dept. of Molecular and Cellular Toxicology)
Disruption mutagenesis by homologous recombination in Saccharomyces cerevisiae is carried out by transforming-DNA fragments containing the target gene disrupted by a selectable marker. A large number of transient (abortive) transformants are often formed that may hinder the isolation of integrants containing the gene disruption. It is shown that abortive transformants result from re-circularization of the linear transforming-DNA in vivo. Their number was greatly reduced when the cut DNA could not readily re-ligate, either by digestions that gave non-compatible or blunt ends, or by de-phosphorylation. In addition, true integrants could be readily distinguished from abortive transformants through replica plating onto selective media. Enhanced disruption-mutagenesis was also observed when non-compatible ends were generated in an ARS-containing insertion vector.
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