Abstract
The temperature-sensitive gametogenesis-defective mutant, gam-1 is sex- limited, expressed only in mating type minus (mt-), and can sexually agglutinate but not fuse at the restrictive temperature (35 degrees C) with gametes of wild type (wt) mt+. Thin-section, freeze-cleave, and scanning electron microscopy reveal that the gam-1 phenotype is dependent on both the temperature at which the cells undergo nitrogen starvation (and therefore gamete formation) and the temperature at which the cells are maintained during the 12 h before mating. Under all conditions of gametogenesis at 35 degrees C, each gam-1 cell produces a normal-appearing membrane-associated mating structure that fails to activate in response to flagellar agglutination. Varying with the conditions of gametogenesis, on the other hand, are the agglutination and signaling properties of the gam-1 flagella. The two mutant phenotypes displayed by gam-1 have been denoted gam-1-I and gam-1-II. An agglutination reaction involving gam-1-I cells does not result in activation of the wt mt+ mating structure. A more stable agglutination reaction, which can result in activation of the wt mt+ mating structure, is characteristic of gam-1-II cells, but because the gam-1 mt- mating sturcture still fails to activate, cell fusion is precluded. We conclude that the gam-1 mutation affects flagellar component(s) involved in establishing an effective, signal-generating agglutination reaction.
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Selected References
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- Bergman K., Goodenough U. W., Goodenough D. A., Jawitz J., Martin H. Gametic differentiation in Chlamydomonas reinhardtii. II. Flagellar membranes and the agglutination reaction. J Cell Biol. 1975 Dec;67(3):606–622. doi: 10.1083/jcb.67.3.606. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Forest C. L., Togasaki R. K. Selection for conditional gametogenesis in Chlamydomonas reinhardi. Proc Natl Acad Sci U S A. 1975 Sep;72(9):3652–3655. doi: 10.1073/pnas.72.9.3652. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goodenough U. W., Hwang C., Martin H. Isolation and genetic analysis of mutant strains of Chlamydomonas reinhardi defective in gametic differentiation. Genetics. 1976 Feb;82(2):169–186. doi: 10.1093/genetics/82.2.169. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goodenough U. W., Weiss R. L. Gametic differentiation in Chlamydomonas reinhardtii. III. Cell wall lysis and microfilament-associated mating structure activation in wild-type and mutant strains. J Cell Biol. 1975 Dec;67(3):623–637. doi: 10.1083/jcb.67.3.623. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SAGER R., GRANICK S. Nutritional control of sexuality in Chlamydomonas reinhardi. J Gen Physiol. 1954 Jul 20;37(6):729–742. doi: 10.1085/jgp.37.6.729. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Snell W. J. Mating in Chlamydomonas: a system for the study of specific cell adhesion. I. Ultrastructural and electrophoretic analyses of flagellar surface components involved in adhesion. J Cell Biol. 1976 Jan;68(1):48–69. doi: 10.1083/jcb.68.1.48. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Solter K. M., Gibor A. Evidence for role of flagella as sensory transducers in mating of Chlamydomonas reinhardi. Nature. 1977 Feb 3;265(5593):444–445. doi: 10.1038/265444a0. [DOI] [PubMed] [Google Scholar]
- Weeks D. P., Collis P. S. Induction of microtubule protein synthesis in Chlamydomonas reinhardi during flagellar regeneration. Cell. 1976 Sep;9(1):15–27. doi: 10.1016/0092-8674(76)90048-9. [DOI] [PubMed] [Google Scholar]
- Weiss R. L., Goodenough D. A., Goodenough U. W. Membrane differentiations at sites specialized for cell fusion. J Cell Biol. 1977 Jan;72(1):144–160. doi: 10.1083/jcb.72.1.144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weiss R. L., Goodenough D. A., Goodenough U. W. Membrane particle arrays associated with the basal body and with contractile vacuole secretion in Chlamydomonas. J Cell Biol. 1977 Jan;72(1):133–143. doi: 10.1083/jcb.72.1.133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Witman G. B., Carlson K., Berliner J., Rosenbaum J. L. Chlamydomonas flagella. I. Isolation and electrophoretic analysis of microtubules, matrix, membranes, and mastigonemes. J Cell Biol. 1972 Sep;54(3):507–539. doi: 10.1083/jcb.54.3.507. [DOI] [PMC free article] [PubMed] [Google Scholar]