Candida albicans strains heterozygous and homozygous for mutations in mitogen-activated protein kinase signaling components have defects in hyphal development.
The Candida albicans genes, CST20 and HST7, were cloned by their ability to suppress the mating defects of Saccharomyces cerevisiae mutants in the ste20 and ste7 genes, which code for elements of the mating mitogenactivated protein (MAP) kinase pathway. These Candida genes are both structural and functional homologs of the cognate Saccharomyces genes. The pattern of suppression in Saccharomyces is related to their presumptive position in the MAP kinase cascade. Null alleles of these genes were constructed in Candida. The Candida homozygous null mutants are defective in hyphal formation on some media, but are still induced to form hyphae by serum, showing that serum induction of hyphae is independent of the MAP kinase cascade. The Candida heterozygotes CST20/cst20 and HST7/hst7 are also defective in hyphal formation. This lack of dominance of the wild-type allele suggests that gene dosage is important in Candida.
Köhler
J R
JR
Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
Fink
G R
GR
D000595:Amino Acid Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D003433:Crosses, Genetic; D005656:Fungal Proteins; D019204:GTP-Binding Proteins; D017353:Gene Deletion; D006579:Heterozygote; D006720:Homozygote; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D011494:Protein Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D005656:Fungal Proteins; D011494:Protein Kinases; C119859:CST20 protein, Candida albicans; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C119846:HST7 protein, Candida albicans; D020929:Mitogen-Activated Protein Kinase Kinases; D019204:GTP-Binding Proteins