Bovine phospholipase C highly homologous to the norpA protein of Drosophila is expressed specifically in cones.
The Drosophila norpA gene encodes a phosphatidylinositol-specific phospholipase C (PI-PLC) expressed predominantly in photoreceptors and involved in phototransduction. However, no direct role for a phospholipase C in vertebrate phototransduction has been identified to date. Recently, we reported the isolation and characterization of bovine cDNAs encoding PI-PLC isoforms expressed predominantly in the retina and with higher homology to the NorpA protein than to any other known PI-PLC. Here, we present evidence that the norpA-homologous bovine retinal PI-PLCs, although found in other retinal neurons as well, are found in cones but not in rods. The results suggest that the phototransduction cascade in cones may utilize phospholipase C in addition to phosphodiesterase.
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Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
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D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003624:Darkness; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D005260:Female; D015870:Gene Expression; D007150:Immunohistochemistry; D008027:Light; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D054799:Phospholipase C beta; D010727:Phosphoric Diester Hydrolases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D011817:Rabbits / Q000276:immunology; D012160:Retina / Q000201:enzymology; D017949:Retinal Cone Photoreceptor Cells / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D010738:Type C Phospholipases
D029721:Drosophila Proteins; D010446:Peptide Fragments; D010727:Phosphoric Diester Hydrolases; D010738:Type C Phospholipases; C468371:NorpA protein, Drosophila; D054801:Phosphoinositide Phospholipase C; D054799:Phospholipase C beta; D043265:Phosphatidylinositol Diacylglycerol-Lyase