Dbf2 is essential for cytokinesis and correct mitotic spindle formation in Candida albicans.
We have characterized the DBF2 gene, encoding a protein kinase of the NDR family in Candida albicans, and demonstrate that this gene is essential for cell viability. Conditional mutants were constructed by using the MET3 promoter to analyse the phenotype of cells lacking this kinase. The absence of Dbf2 resulted in cells arrested as large-budded pairs that failed to contract the actomyosin ring, a function similar to that described for its Saccharomyces cerevisiae orthologue. In addition to its role in cytokinesis, Dbf2 regulates mitotic spindle organization and nuclear segregation as Dbf2-depleted cells have abnormal microtubules and severe defects in nuclear migration to the daughter cell, which results in a cell cycle block during mitosis. Taken together, these results imply that Dbf2 performs several functions during exit from mitosis and cytokinesis. Consistent with a role in spindle organization, the protein localizes to the mitotic spindle during anaphase, and it interacts physically with tubulin, as indicated by immunoprecipitation experiments. Finally, DBF2 depletion also resulted in impaired true hyphal growth.
González-Novo
Alberto
A
Dpto. Microbiología y Genética, Instituto de Microbiología Bioquímica, Universidad de Salamanca/CSIC, Avda. Doctores de la Reina s/n. 37007 Salamanca, Spain.
Labrador
Leticia
L
Pablo-Hernando
M Evangelina
ME
Correa-Bordes
Jaime
J
Sánchez
Miguel
M
Jiménez
Javier
J
Vázquez de Aldana
Carlos R
CR
D000205:Actomyosin / Q000378:metabolism; D002176:Candida albicans / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D020043:Genes, Essential; D005800:Genes, Fungal; D025301:Hyphae / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism; D009154:Mutation; D008941:Spindle Apparatus / Q000378:metabolism*
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D000205:Actomyosin