Conditional mutants of meiosis in yeast.
Three temperature-sensitive mutants, spo1-1, spo2-1, and spo3-1, were characterized with respect to their behavior in sporulation medium at a restrictive temperature. The time of expression of the functions defective in the mutants was determined by temperature-shift experiments during the sporulation process. In addition, each mutant was examined for the following: (i) its ability to undergo the nuclear divisions of meiosis; (ii) deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis; (iii) protein turnover; and (iv) colony-forming ability after exposure to sporulation medium. Mutant spo1-1 is defective in a function which confers a temperature-sensitive period which extends over 32% of the sporulation cycle. The temperature-sensitive period of mutant spo2-1 occupies 34% of the cycle, whereas the temperature-sensitive period of mutant spo3-1 extends over 2% of the sporulation cycle. Cytological evidence indicates that all three mutants initiate but do not complete the meiotic nuclear divisions. The DNA content of sporulation cultures of mutants spo1-1 and spo3-1 did not increase to the wild-type level; DNA synthesis in spo2-1 was normal. All three strains exhibit a loss of colony-forming ability during incubation in sporulation medium at the restrictive temperature. RNA and protein synthesis and protein turnover occur in the mutants.
D000225:Adenine / Q000378:metabolism; D001120:Arginine / Q000378:metabolism; D002247:Carbon Isotopes; D004247:DNA / Q000096:biosynthesis; D005827:Genetics, Microbial; D008540:Meiosis; D009154:Mutation; D010649:Phenylalanine / Q000378:metabolism; D010759:Phosphorus Isotopes; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis; D012440:Saccharomyces / Q000166:cytology* / Q000254:growth & development; D013170:Spores / Q000254:growth & development; D013696:Temperature
D002247:Carbon Isotopes; D010759:Phosphorus Isotopes; D010649:Phenylalanine; D012313:RNA; D004247:DNA; D001120:Arginine; D000225:Adenine