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We isolated two S. pombe genes, scd1 and scd2, that are required for normal morphology and mating. scd1 and scd2 are homologous to CDC24 and BEM1, respectively, of S. cerevisiae. Epistasis analyses indicate that scd2 and ras1 converge upon scd1, which, in turn, interacts with cdc42sp, a RHO-like GTPase. Studies with the yeast two-hybrid system indicate that(More)
Schizosaccharomyces pombe contains a single gene, ras1, which is a homolog of the mammalian RAS genes. ras1 is required for conjugation, sporulation, and normal cell shape. ras1 has been previously identified as ste5. We report here a gene we call byr2 that can encode a predicted protein kinase and can partially suppress defects in ras1 mutants. ras1 mutant(More)
The regulation of acetylcholine receptor alpha-subunit gene expression was analyzed by transient expression assays. Using rabbit beta-globin cDNA as a reporter gene, we have confirmed that the 5'-flanking sequence of the chicken acetylcholine receptor alpha-subunit gene directs specific expression in differentiated C2C12 cells, a mouse muscle cell line, but(More)
We present genetic evidence that three presumptive protein kinases of Schizosaccharomyces pombe, byr2, byr1, and spk1 that are structurally related to protein kinases of Saccharomyces cerevisiae, STE11, STE7, and FUS3, respectively, are also functionally related. In some cases, introduction of the heterologous protein kinase into a mutant was sufficient for(More)
We have designed a vector to express the mammalian GAP protein in the yeast S. cerevisiae. When expressed in yeast, GAP inhibits the function of the human H-rasgly12 protein, but not that of the H-rasval12 protein, and complements the loss of IRA1. IRA1 is a yeast gene that encodes a protein with homology to GAP and acts upstream of RAS. Mammalian GAP can(More)
The interaction between RAS proteins and adenylyl cyclase was studied by using dominant interfering mutations of adenylyl cyclase from the yeast Saccharomyces cerevisiae. RAS proteins activate adenylyl cyclase in this organism. A plasmid expressing a catalytically inactive adenylyl cyclase was found to interfere dominantly with this activation. The(More)
Byr3 was selected as a multicopy suppressor of the sporulation defects of diploid Schizosaccharomyces pombe cells that lack ras1. Like cells mutant at byr1 and byr2, two genes that encode putative protein kinases and that in multiple copies are also suppressors of the sporulation defects of ras1 null diploid cells, cells mutant at byr3 are viable but(More)
Our laboratory focuses on two general areas: signal transduction and growth control. Much of our work centers about the RAS proteins, small guanine-nucleotide-binding proteins, which reside on the in­ ner surface of the plasma membrane, that have been highly conserved in evolution and play a critical role in mediating signals that control cellular growth(More)
Our laboratory continues to study signal transduction, with the main focus on RAS-dependent signal trans­ duction. In the yeast Saccharomyces cerevisiae, RAS proteins regulate adenylyl cyclase. The mechanism by which they do this is unknown, and this is not their only function. Since activation of adenylyl cy­ clase is not the function of mammalian RAS, the(More)