Skip to main content
NCBI home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1983 Oct;156(1):155–160. doi: 10.1128/jb.156.1.155-160.1983

Kinetics of the nuclear division cycle of Aspergillus nidulans.

L G Bergen, N R Morris
PMCID: PMC215064  PMID: 6352675

Abstract

We have analyzed the cell cycle kinetics of Aspergillus nidulans by using the DNA synthesis inhibitor hydroxyurea (HU) and a temperature-sensitive cell cycle mutant nimT that blocks in G2. HU rapidly inhibits DNA synthesis (S), and as a consequence progression beyond S to mitosis (M) is blocked. Upon removal of HU the inhibition is rapidly reversible. Conidia (asexual spores) of nimT were germinated at restrictive temperature to synchronize germlings in G2 and then downshifted to permissive temperature in the presence of HU. This procedure synchronizes the germlings at the beginning of S in the second cell cycle after spore germination. We have measured the total duration of S, G2, and M as the time required for these cells to recover from the HU block and undergo the next nuclear division. The duration of S was defined by the time course of sensitivity to reintroduction of HU during recovery from the initial HU block. The cell cycle time was measured as the nuclear doubling time, and the duration of mitosis was determined from the mitotic index. The duration of G1 was calculated by subtracting the combined durations of S, G2, and M from the nuclear doubling time, and the length of G2 was calculated by subtracting S and M from the aggregate length of S, G2, and M. We have also determined the duration of the phases of the cell cycle during the first cycle after spore germination. In these experiments spores were germinated directly in HU without first being blocked in G2. Because the durations of G1, S, G2, and M for the first cell cycle after spore germination were identical with those previously determined for spores presynchronized at the beginning of S in the second cell cycle, we conclude that dormant conidia of A. nidulans are arrested at, or before, the start of S.

Full text

PDF
155

Images in this article

158Image
on p.158

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Byers B., Goetsch L. Behavior of spindles and spindle plaques in the cell cycle and conjugation of Saccharomyces cerevisiae. J Bacteriol. 1975 Oct;124(1):511–523. doi: 10.1128/jb.124.1.511-523.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Byers B., Goetsch L. Duplication of spindle plaques and integration of the yeast cell cycle. Cold Spring Harb Symp Quant Biol. 1974;38:123–131. doi: 10.1101/sqb.1974.038.01.016. [DOI] [PubMed] [Google Scholar]
  3. Grivell A. R., Jackson J. F. Thymidine kinase: evidence for its absence from Neurospora crassa and some other micro-organisms, and the relevance of this to the specific labelling of deoxyribonucleic acid. J Gen Microbiol. 1968 Dec;54(2):307–317. doi: 10.1099/00221287-54-2-307. [DOI] [PubMed] [Google Scholar]
  4. Hereford L. M., Hartwell L. H. Sequential gene function in the initiation of Saccharomyces cerevisiae DNA synthesis. J Mol Biol. 1974 Apr 15;84(3):445–461. doi: 10.1016/0022-2836(74)90451-3. [DOI] [PubMed] [Google Scholar]
  5. Kessel M., Rosenberger R. F. Regulation and timing of deoxyribonucleic acid synthesis in hyphae of Aspergillus nidulans. J Bacteriol. 1968 Jun;95(6):2275–2281. doi: 10.1128/jb.95.6.2275-2281.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Morris N. R., Kirsch D. R., Oakley B. R. Molecular and genetic methods for studying mitosis and spindle proteins in Aspergillus nidulans. Methods Cell Biol. 1982;25(Pt B):107–130. doi: 10.1016/s0091-679x(08)61422-3. [DOI] [PubMed] [Google Scholar]
  7. Morris N. R., Lai M. H., Oakley C. E. Identification of a gene for alpha-tubulin in Aspergillus nidulans. Cell. 1979 Feb;16(2):437–442. doi: 10.1016/0092-8674(79)90019-9. [DOI] [PubMed] [Google Scholar]
  8. Morris N. R. Mitotic mutants of Aspergillus nidulans. Genet Res. 1975 Dec;26(3):237–254. doi: 10.1017/s0016672300016049. [DOI] [PubMed] [Google Scholar]
  9. Oakley B. R., Morris N. R. A mutation in Aspergillus nidulans that blocks the transition from interphase to prophase. J Cell Biol. 1983 Apr;96(4):1155–1158. doi: 10.1083/jcb.96.4.1155. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Oakley B. R., Morris N. R. Nuclear movement is beta--tubulin-dependent in Aspergillus nidulans. Cell. 1980 Jan;19(1):255–262. doi: 10.1016/0092-8674(80)90407-9. [DOI] [PubMed] [Google Scholar]
  11. Orr E., Rosenberger R. F. Initial characterization of Aspergillus nidulans mutants blocked in the nuclear replication cycle. J Bacteriol. 1976 May;126(2):895–902. doi: 10.1128/jb.126.2.895-902.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Robinow C. F., Caten C. E. Mitosis in Aspergillus nidulans. J Cell Sci. 1969 Sep;5(2):403–431. doi: 10.1242/jcs.5.2.403. [DOI] [PubMed] [Google Scholar]
  13. Rosenberger R. F., Kessel M. Synchrony of nuclear replication in individual hyphae of Aspergillus nidulans. J Bacteriol. 1967 Nov;94(5):1464–1469. doi: 10.1128/jb.94.5.1464-1469.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Schindler D., Davies J. Inhibitors of macromolecular synthesis in yeast. Methods Cell Biol. 1975;12:17–38. doi: 10.1016/s0091-679x(08)60949-8. [DOI] [PubMed] [Google Scholar]
  15. Sheir-Neiss G., Lai M. H., Morris N. R. Identification of a gene for beta-tubulin in Aspergillus nidulans. Cell. 1978 Oct;15(2):639–647. doi: 10.1016/0092-8674(78)90032-6. [DOI] [PubMed] [Google Scholar]
  16. Slater M. L. Effect of reversible inhibition of deoxyribonucleic acid synthesis on the yeast cell cycle. J Bacteriol. 1973 Jan;113(1):263–270. doi: 10.1128/jb.113.1.263-270.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Walters R. A., Tobey R. A., Ratliff R. L. Cell-cycle-dependent variations of deoxyribonucleoside triphosphate pools in Chinese hamster cells. Biochim Biophys Acta. 1973 Sep 7;319(3):336–347. doi: 10.1016/0005-2787(73)90173-1. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES