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Myosin‐II is Necessary for Septum Formation in Aspergillus nidulans
Author(s) -
Wang Xiao,
Du Wenbin,
Hoge Brianna L.,
Jackson-Hayes Loretta,
Hill Terry W.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.781.1
Subject(s) - aspergillus nidulans , biology , mutant , complementation , genetics , mutation , chitin synthase , cytokinesis , gene , multinucleate , microbiology and biotechnology , biochemistry , cell , cell division , chitin , chitosan
Cytokinesis in filamentous fungi involves the progressive inward growth of the cell wall and plasma membrane, resulting in a series of functionally connected multinucleate compartments, delimited by crosswalls termed septa. The process of septation, despite intensive study, is still incompletely understood. By screening chemically mutagenized strains of the model fungus Aspergillus nidulans , we have identified several isolates with impaired septum formation, which complementation studies using previously‐identified Aspergillus nidulans “ sep ” mutations show to be mutations in novel loci. Here we report that the mutation in one of these strains (RCH‐2) occurs in the gene that encodes the fungal homologue of mammalian myosin II ( MyoB , AN4706). Sequencing of the MyoB allele in the RCH‐2 mutant reveals a point mutation that is predicted to result in a glycine‐to‐aspartate amino acid substitution at residue 843 in the myosin‐II converter domain. This residue is conserved in all fungal, plant, and animal myosin‐II sequences that we have examined. Down‐regulation of wild‐type MyoB expression under control of the A. nidulans AlcA promoter replicates the septation‐minus phenotype of the RCH‐2 mutation. A GFP‐tagged version of MyoB localizes to constricting septal rings in a manner consistent with the protein's involvement in the process of septation.