ISSN:
1617-4623
Keywords:
Centromere
;
Mini-chromosome
;
Partial aneuploidy
;
Schizosaccharomyces pombe
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary A highly stable, partial aneuploid, HM248, of the fission yeast Schizosaccharomyces pombe was obtained from the unstable aneuploid disomic for chromosome III by γ-irradiation. It contained a 500 kb mini-chromosome (designated Ch16) that was separated as a single band by pulsed field gradient electrophoresis. Genetic analysis showed that Ch16 was deleted for most of chromosome III except for the pericentric region; three centromere-linked markers encompassing the centromere region remained. This was further substantiated by integrating the cloned fragments of Ch16 DNA extracted from the agarose gel; integrations took place in the pericentric region. A 400 kb derivative (Ch16D1) was constructed which appeared to lack a part of Ch16. A single haploid cell of S. pombe could stably maintain Ch16 and Ch16D1 in addition to the three regular chromosomes. Ch16 was visualized as a minute chromosomal body in the nucleus of a β-tubulin mutant under restrictive conditions. A single copy of Ch16 was highly stable and behaved like a natural chromosome in mitosis and meiosis. The frequency of chromosomal loss was 10-4. In meiosis, it segregated independently of the regular chromosome III. Segregation of two Ch16s per cell could be monitored by specifically marked Ch16s containing the Saccharomyces cerevisiae LEU2 gene (designated Ch16LE) of the fluorouracil resistance marker (Ch16FR). Two copies of Ch16 were mitotically unstable (chromosomal loss, 10-3) and frequently failed in meiotic segregation. The frequency of meiotic recombination between the two Ch16s was greatly reduced.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00422063
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