Cloning of a Cryptococcus neoformans gene, GPA1, encoding a G-protein alpha-subunit homolog.
We have isolated a gene, GPA1, from Cryptococcus neoformans by the PCR technique. DNA sequencing of the GPA1 clone suggested that it encodes a protein homologous to the G-protein alpha-subunit family. Comparison of the deduced amino acid sequence of the GPA1-encoded protein revealed that it is about 45% identical to several mammalian Gi alpha subunits and 48% identical to the G alpha protein Gpa2 from Saccharomyces cerevisiae. G alpha proteins are known to be involved in mating of other yeasts, such as S. cerevisiae and Schizosaccharomyces pombe. Southern analysis demonstrated that GPA1 is present in a single copy within the Cryptococcus genome. Isolation of the cDNA for GPA1 confirmed that the gene contains six introns within the coding region. The GPA1 transcript was identified by Northern (RNA) analysis as a 1.6-kb RNA present in exponentially growing cells of both the alpha and a mating types. Moreover, the abundance of this transcript increased in cells shifted to starvation medium. Coincubation of alpha and a cells on starvation medium is required for mating of cryptococcal cells. Thus, our results are consistent with the involvement of C. neoformans GPA1 in mating.
Tolkacheva
T
T
Department of Microbiology, University of Nevada School of Medicine, Reno 89557-0046.
McNamara
P
P
Piekarz
E
E
Courchesne
W
W
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003455:Cryptococcus neoformans / Q000235:genetics*; D044385:GTP-Binding Protein alpha Subunits; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D019204:GTP-Binding Proteins / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D020962:Heterotrimeric GTP-Binding Proteins; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D012098:Reproduction / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014158:Transcription, Genetic
D044385:GTP-Binding Protein alpha Subunits; D029701:Saccharomyces cerevisiae Proteins; D019204:GTP-Binding Proteins; C084293:GPA1 protein, S cerevisiae; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins