Outer plaque assembly and spore encapsulation are defective during sporulation of adenylate cyclase-deficient mutants of Saccharomyces cerevisiae.
Sporulation in diploid cells homozygous for the cyr1-2 mutation of the yeast Saccharomyces cerevisiae was examined. This mutation causes a defect in adenylate cyclase and temperature-sensitive arrest in the G1 phase of the mitotic cell cycle. The cyr1-2/cyr1-2 diploid cells were able to initiate meiotic divisions, but produced predominantly two-spored asci at the restrictive temperature. Temperature-sensitive period for production of two-spored asci was approximately 12 h after the transfer of cells to the sporulation medium. The levels of cAMP increased during this period in the wild type and cyr1-2/cyr1-2 diploid cells incubated at the permissive temperature, but remained at an extremely low level in the cyr1-2/cyr1-2 diploid cells incubated at the restrictive temperature. Dyad analysis of the cyr1-2 strain indicated that meiotic products were randomly included into ascospores. Fluorescent microscopy of the cyr1-2/cyr1-2 diploid cells incubated at the restrictive temperature revealed that individual haploid nuclei were enclosed in each of the two spores after meiosis. About half of the cyr1-2/cyr1-2 diploid cells entered normal meiosis 1 producing two normal spindle pole bodies with inner and outer plaques, and the other half entered abnormal meiosis 1 producing one normal spindle pole body and one defective spindle pole body without out plaque. At meiosis II, some cells contained a pair of normal spindle pole bodies and other cells contained pairs of normal and abnormal spindle pole bodies.
Uno
I
I
Matsumoto
K
K
Hirata
A
A
Ishikawa
T
T
D000262:Adenylyl Cyclases / Q000235:genetics / Q000502:physiology*; D002467:Cell Nucleus / Q000648:ultrastructure; D000242:Cyclic AMP / Q000502:physiology; D006358:Hot Temperature; D007399:Interphase; D007700:Kinetics; D008540:Meiosis; D008854:Microscopy, Electron; D008938:Mitosis; D009154:Mutation; D010641:Phenotype; D011419:Propidium; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000502:physiology* / Q000648:ultrastructure; D013172:Spores, Fungal; D013194:Staining and Labeling
D011419:Propidium; D000242:Cyclic AMP; D000262:Adenylyl Cyclases