Genomic organization of a Drosophila phospholipase C, norpA, and molecular lesions in two temperature-sensitive mutants.
The Drosophila mutant no receptor potential A (norpA) is the phototransduction-defective mutant which lacks phosphatidylinositol-specific phospholipase C (PI-PLC) activity. Recently, norpA cDNA was isolated and its homology to a bovine PI-PLC was demonstrated [Bloomquist, B.T. et al. (1988) Cell 54, 723-733]. On the basis of its cDNA, we determined the genomic organization of the norpA gene and revealed that the norpA gene consists of 13 coding exons spreading over a 15 kb genomic area. Furthermore, we identified the mutational sites of two temperature-sensitive (ts) mutants. The analysis of norpAH52 revealed that the single amino acid change from Ser-551 to Tyr causes the PI-PLC activity to become temperature-sensitive. The other allele, norpAKO50, has two substitutions from Ser-406 to Phe and from Gly-451 to Ser. These three mutations are located in regions highly conserved in other mammalian PI-PLC molecules. This suggests that these regions are important for PI-PLC catalytic activity.
Department of Physics, Faculty of Science, University of Tokyo.
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Masai
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Hotta
D000483:Alleles; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004331:Drosophila melanogaster / Q000235:genetics*; D005091:Exons; D016678:Genome; D015698:Genomic Library; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D013696:Temperature; D014158:Transcription, Genetic; D010738:Type C Phospholipases / Q000235:genetics*
D000596:Amino Acids; D010738:Type C Phospholipases