期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1979
卷号：76
期号：4
页码：1952-1956
DOI：10.1073/pnas.76.4.1952
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The {Psi}+ extrachromosomal determinant in the yeast Saccharomyces cerevisiae suppresses certain UAA markers and increases the efficiency of suppression of UAA suppressors and certain frameshift suppressors. Although the exact nature of {Psi}+ determinant is unknown, it is believed to be a self-replicating cytoplasmic factor affecting some component of the translational machinery. In this report we describe growth conditions for efficient mutation or elimination of the {Psi}+ determinant. Incubation of {Psi}+ cultures in hypertonic nutrient medium resulted in rapid conversion to a culture containing predominantly {Psi}- cells during the growth cycle. The kinetics of {Psi}+ to {Psi}- conversion established that the occurrence of {Psi}- cells was due to induction and not to selection of pre-existing {Psi}- cells. The results suggest that the replication of the {Psi}+ determinant is sensitive to hypertonic conditions.
