We isolated three highly homologous genes, PIR1, PIR2 and PIR3, collectively called the PIR genes. The remarkable feature of their putative amino acid sequence is that they contain a sequence consisting of 18-19 amino acid residues repeated tandemly seven to ten times. Genes homologous to PIR were found in Kluyveromyces lactis and Zygosaccharomyces rouxii but not in Schizosaccharomyces pombe, suggesting that a set of PIR genes plays some role in budding yeast. Bias of codon usage seen in each of the PIR translation products suggests that they are expressed abundantly. The fact that disruption of each gene is viable indicates that none of them is essential. The double disruptants, pir1 pir2, were viable under various conditions, such as higher temperature (37 degrees C) or high salt concentration, but showed a slow-growing phenotype on an agar slab. Furthermore, they were sensitive to heat shock. Addition of a pir3 disruption to the pir1 pir2 double disruptant brought about no phenotypic difference from the original double mutant. PIR1 and PIR3 are closely linked to each other and are on chromosome XI.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.