Aspergillus nidulans has proven to be an excellent model organism for investigating aspects of general cell cycle regulation and development. In particular, our understanding of the regulation of mitosis was advanced by determining the presence and function of major mitotic regulatory factors, some of which for the first time, in this organism. The Polo-like kinases are a relatively new family of cell cycle regulators implicated in various stages of mitosis, as well as cytokinesis and septation. Despite their widespread occurrence, ranging from yeast to human cells, their precise functions and regulation are not clear. To date, Polo-like kinases have not been described in any filamentous fungus. In order to progress our understanding of mitosis and development in Aspergillus and higher organisms, and to elucidate potential functions and interactions of Polo-like kinases with other mitotic factors, such as NIMA kinase, we investigated the presence of a Polo-like kinase in Aspergillus. A full length clone was isolated, using RACE PCR with primers designed against sequences in Aspergillus EST's with similarity to conserved regions of the Polo sequence. The genomic clone was recovered from chromosome 7 of a cosmid library. The genomic and cDNA clones were similar in size, at approximately 3.8 kb. Sequencing the genomic clone revealed high similarity to the Polo-like kinases across the amino-terminal, catalytic domain, and within the carboxy-terminal Polo box, a conserved region defining Polo-like kinases. Manipulation of the gene, including overexpression at various stages of the cell cycle and molecular deletion, are underway to help determine the function of the gene and its contribution to cell cycle progression in Aspergillus.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)