An abnormal cell division cycle in an AIR carboxylase-deficient mutant of the fission yeastSchizosaccharomyces pombe
✍ Scribed by Junpei Ishiguro
- Publisher
- Springer-Verlag
- Year
- 1989
- Tongue
- English
- Weight
- 359 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0172-8083
No coin nor oath required. For personal study only.
✦ Synopsis
Adenine-requiring mutant strains of S. pombe enter the stationary phase after depleting a culture medium of adenine or its analogues. Stationary phase cells of six mutants defective at different stages of the purine nucleotide synthetic pathway were examined for cell volume and DNA content, and then compared in these respects with those ofa prototrophic wild-type strain. The cell cycle of the wild-type strain was arrested in the G 2 phase (2C state) in the nitrogen rich medium, as is evident from DNA content per cell (0.0425 pg) and cell volume (47.7 ~tm3). An AIR carboxylase-deficient (ade6) mutant strain was found to have an unusual cell volume (307.4 ~tm 3) and DNA content (0.1187 pg). By DAPI fluorescence microscopy, each mutant cell was seen to contain only one enlarged nucleus, which indicates the absence of cell populations containing cells in the 4C state of the S phase following nuclear division. It then follows that in ade6 mutant ceils, DNA synthesis occurs in the absence of a completed nuclear division. Thus in S. pombe cells, the completion of nuclear division is not necessarily required for the next cycle initiation of DNA synthesis under certain physiological conditions.