Role of the Cell-cycle-regulated NIMA Protein Kinase during G2 and Mitosis: Evidence for Two Pathways of Mitotic Regulation
This extract was created in the absence of an abstract.
Excerpt
Temperature-sensitive mutations of nimA in Aspergillus nidulans cause an arrest of the cell cycle late in G2 at the restrictive temperature (Morris 1976; Bergen et al. 1984). Cells arrest with a duplicated spindle pole body and a stable array of cytoplasmic microtubules, and no spindle formation or chromosome condensation occurs. Returning arrested cells to the permissive temperature promotes a rapid and synchronous mitosis to take place, during which the mitotic spindle is formed and chromosomes condense within 5 minutes (Oakley and Morris 1983). nimA has been cloned by complementation of the nimA5 mutation, and elevated levels of nimA mRNA have been shown to correlate positively with mitosis (Osmani et al. 1987). Sequence analysis of nimA cDNA indicates that nimA encodes a potential serine/threonine protein kinase. Gross over-expression of the putative protein kinase encoded by nimA promotes premature mitosis and leads to an arrest of nuclei in a pseudometaphase state (Osmani...
