Tissue- and cell-specific expression of Ins(1,4,5)P3 3-kinase isoenzymes.
The phosphorylation of Ins(1,4,5)P3 (InsP3) to Ins(1,3,4,5)P4 (InsP4) is catalysed by InsP3 3-kinase. Molecular-biological data have shown the presence of two human isoenzymes of InsP3 3-kinase, namely InsP3 3-kinases A and B. We have isolated from a rat thymus cDNA library a 2235 bp cDNA (clone B15) encoding rat InsP3 3-kinase B. Northern-blot analysis of mRNA isolated from rat tissues (thymus, testis, brain, spleen, liver, kidney, heart, lung and intestine) revealed that a rat InsP3 3-kinase B probe hybridized to a 6 kb mRNA in lung, thymus, testis, brain and heart. In contrast, Northern-blot analysis of the same tissues probed under stringent conditions with a rat InsP3 3-kinase A probe hybridized to a 2 kb mRNA only in brain and a 1.8-2.0 kb mRNA species in testis. Northern-blot analysis of three human cell lines (HL-60, SH-SY5Y and HTB-138) probed with a human InsP3 3-kinase B probe showed the presence of a 6 kb mRNA in all cell lines, except in the human neuroblastoma cell line (SH-SY5Y), where two mRNA species of 5.7 and 6 kb were detected. Using the same blot, no hybridization signal could be seen with a human InsP3 3-kinase A probe. Altogether, our data are consistent with the notion that the two InsP3 3-kinase isoenzymes, A and B, are specifically expressed in different tissues and cells.
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Interdisciplinary Research Institute (IRIBHN), Brussels, Belgium.
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D015870:Gene Expression; D005910:Glioma; D006624:Hippocampus / Q000737:chemistry; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics*; D015473:Leukemia, Promyelocytic, Acute; D008969:Molecular Sequence Data; D009447:Neuroblastoma; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D013950:Thymus Gland / Q000737:chemistry; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D017853:Phosphotransferases (Alcohol Group Acceptor); C051038:Inositol 1,4,5-trisphosphate 3-kinase