Abstract
Diploid cells of Tetrahymena thermophila were crossed to strain A*V, whose micronucleus is defective, to induce the unilateral transfer of gametic nuclei from the diploid cells to the A*V cells (round I of genomic exclusion). These haploid nuclei presumably undergo one endomitotic cycle and then become diploid with a G(1) (2C) DNA content. However, further DNA replication from 2C to 4C was transiently arrested until the pairs separated. When endomitosis was blocked by treatment with cycloheximide during 6-8 hours of conjugation, the exconjugants of round I of genomic exclusion remained haploid. Competence for diploidization is apparently limited to some period of time after nuclear transfer. Blocking of diploidization during round I of genomic exclusion can be used as an efficient way to induce haploid strains in Tetrahymena.
Full Text
The Full Text of this article is available as a PDF (2.6 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen S. L. Cytogenetics of genomic exclusion in Tetrahymena. Genetics. 1967 Apr;55(4):797–822. doi: 10.1093/genetics/55.4.797. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Allis C. D., Colavito-Shepanski M., Gorovsky M. A. Scheduled and unscheduled DNA synthesis during development in conjugating Tetrahymena. Dev Biol. 1987 Dec;124(2):469–480. doi: 10.1016/0012-1606(87)90500-8. [DOI] [PubMed] [Google Scholar]
- Bleyman L. K., Bruns P. J. Genetics of cycloheximide resistance in Tetrahymena. Genetics. 1977 Oct;87(2):275–284. doi: 10.1093/genetics/87.2.275. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bruns P. J., Brussard T. B. Positive selection for mating with functional heterokaryons in Tetrahymena pyriformis. Genetics. 1974 Nov;78(3):831–841. doi: 10.1093/genetics/78.3.831. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bruns P. J., Brussard T. E. Nullisomic tetrahymena: eliminating germinal chromosomes. Science. 1981 Jul 31;213(4507):549–551. doi: 10.1126/science.213.4507.549. [DOI] [PubMed] [Google Scholar]
- Kaney A. R. A transmissible developmental block in Tetrahymena thermophila. Exp Cell Res. 1985 Apr;157(2):315–321. doi: 10.1016/0014-4827(85)90116-8. [DOI] [PubMed] [Google Scholar]
- Kaney A. R., Speare V. J. An amicronucleate mutant of Tetrahymena thermophila. Exp Cell Res. 1983 Feb;143(2):461–467. doi: 10.1016/0014-4827(83)90074-5. [DOI] [PubMed] [Google Scholar]
- Martindale D. W., Allis C. D., Bruns P. J. Conjugation in Tetrahymena thermophila. A temporal analysis of cytological stages. Exp Cell Res. 1982 Jul;140(1):227–236. doi: 10.1016/0014-4827(82)90172-0. [DOI] [PubMed] [Google Scholar]
- Newport J. W., Kirschner M. W. Regulation of the cell cycle during early Xenopus development. Cell. 1984 Jul;37(3):731–742. doi: 10.1016/0092-8674(84)90409-4. [DOI] [PubMed] [Google Scholar]
- Preparata R. M., Nanney D. L. Cytogenetics of triplet conjugation in Tetrahymena: origin of haploid and triploid clones. Chromosoma. 1977 Mar 7;60(1):49–57. doi: 10.1007/BF00330410. [DOI] [PubMed] [Google Scholar]
- Roth J., Cleffmann G. Pattern of DNA increase in macronuclear anlagen of Tetrahymena. J Cell Sci. 1986 Jul;83:155–164. doi: 10.1242/jcs.83.1.155. [DOI] [PubMed] [Google Scholar]
- Seyfert H. M., Preparata R. M. The regulation of amounts and proportions of genetic elements in the macronuclei of Tetrahymena thermophila strains of diverse karyotype. J Cell Sci. 1979 Dec;40:111–123. doi: 10.1242/jcs.40.1.111. [DOI] [PubMed] [Google Scholar]
- Weindruch R. H., Doerder F. P. Age-dependent micronuclear deterioration in Tetrahymena pyriformis, syngen 1. Mech Ageing Dev. 1975 May-Aug;4(3-4):263–279. doi: 10.1016/0047-6374(75)90028-7. [DOI] [PubMed] [Google Scholar]