cDNA sequence and gene locus of the human retinal phosphoinositide-specific phospholipase-C beta 4 (PLCB4).
Defects in the Drosophila norpA (no receptor potential A) gene encoding a phosphoinositide-specific phospholipase C (PLC) block invertebrate phototransduction and lead to retinal degeneration. The mammalian homolog, PLCB4, is expressed in rat brain, bovine cerebellum, and the bovine retina in several splice variants. To determine a possible role of PLCB4 gene defects in human disease, we isolated several overlapping cDNA clones from a human retina library. The composite cDNA sequence predicts a human PLC beta 4 polypeptide of 1022 amino acid residues (MW 117,000). This PLC beta 4 variant lacks a 165-amino-acid N-terminal domain characteristic for the rat brain isoforms, but has a distinct putative exon 1 unique for human and bovine retina isoforms. A PLC beta 4 monospecific antibody detected a major (130 kDa) and a minor (160 kDa) isoform in retina homogenates. Somatic cell hybrids and deletion panels were used to localize the PCLB4 gene to the short arm of chromosome 20. The gene was further sublocalized to 20p12 by fluorescence in situ hybridization.
Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA.
R A
RA
Alvarez
A J
AJ
Ghalayini
P
P
Xu
A
A
Hardcastle
S
S
Bhattacharya
P N
PN
Rao
M J
MJ
Pettenati
R E
RE
Anderson
W
W
Baehr
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D002417:Cattle; D002531:Cerebellum / Q000201:enzymology; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D004330:Drosophila / Q000201:enzymology / Q000235:genetics; D029721:Drosophila Proteins; D015723:Gene Library; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells; D017404:In Situ Hybridization, Fluorescence; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics*; D007621:Karyotyping; D008969:Molecular Sequence Data; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054799:Phospholipase C beta; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D012160:Retina / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D010738:Type C Phospholipases
D018076:DNA, Complementary; D029721:Drosophila Proteins; D007527:Isoenzymes; D010727:Phosphoric Diester Hydrolases; D010738:Type C Phospholipases; C468371:NorpA protein, Drosophila; D054799:Phospholipase C beta; D043265:Phosphatidylinositol Diacylglycerol-Lyase