Septum formation inAspergillus nidulans

Abstract

We are investigating septation in Aspergillus nidulans. We have shown that septum formation is dependent on the third nuclear division and actin is involved in this process. We have also characterized nine temperature-sensitive septation (sep) mutants. On the basis of our analysis we have divided these mutants into three phenotypic classes. We are uncovering the order of events in the septation pathway by analysis of double mutants constructed with different pairs of sep mutants. The sepB gene has been cloned and sequenced. Homology with the Saccharomyces cerevisiae CTF4 gene and the phenotype of the sepB mutant support a role in monitoring the fidelity of chromosome transmission. We are also investigating the role of the asp genes (Aspergillus septins). Three asp genes were identified by homology with the S. cerevisiae septins. aspB has been cloned, sequenced, and fused to a biotinylated tag for antibody production. Antibody production and localization studies are now underway. Because septation requires the integration of several cellular processes, our studies should give insight into the cell cycle, cell wall biosnythesis and development of A. nidulans. Key words: septation, cytokinesis, Aspergillus nidulans.