Molecular cloning of a human co-beta-glucosidase cDNA: evidence that four sphingolipid hydrolase activator proteins are encoded by single genes in humans and rats.
Authentic cDNAs encoding the activator protein for acid beta-glucosidase (EC3.2.1.45), co-beta-glucosidase, were cloned from the pCD and lambda gt11 human cDNA libraries. Initial screening with oligonucleotide mixtures encoding amino acid sequences of co-beta-glucosidase identified partial cDNAs which were used to obtain a potentially full-length cDNA from the lambda gt11 library. This clone (2767 bp), EGTISI, contained 5' (38 bp) and 3' (1157 bp) noncoding sequences, a translation initiation site, and an open reading frame encoding 524 amino acids which included a typical hydrophobic signal sequence (16 amino acids). Computer analyses identified three regions of high similarity to co-beta-glucosidase encoded by tandem sequences in EGTISI. Searches revealed that two of these regions encoded peptides of known function; SAP1 (sphingolipid activator protein 1) and protein C (a new sphingolipid activator protein) were encoded by EGTISI sequences 5' and 3', respectively, to those for co-beta-glucosidase. The third region of similarity, encoding a theoretical peptide (undefined function), was located most 5' in the cDNA. EGTISI and its encoded polypeptide had high similarity (77% nucleotide identity and about 80% amino acid similarity) to a rat Sertoli cell cDNA and its encoded sulfated glycoprotein-1. These results indicate that a single highly conserved gene encodes the precursor for four potential sphingolipid activator proteins in rat and man.
Rorman
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EG
Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029.
Grabowski
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GA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D051152:Clusterin; D004789:Enzyme Activation; D005091:Exons; D005260:Female; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007438:Introns; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D011247:Pregnancy; D011486:Protein C / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D051381:Rats; D049231:Saposins; D012689:Sequence Homology, Nucleic Acid; D049128:Sphingolipid Activator Proteins; D001617:beta-Glucosidase / Q000378:metabolism
C495242:CLU protein, human; D051152:Clusterin; D006023:Glycoproteins; D018832:Molecular Chaperones; C483345:PSAP protein, human; D011486:Protein C; D011498:Protein Precursors; D011506:Proteins; C483347:Psap protein, rat; D049231:Saposins; D049128:Sphingolipid Activator Proteins; D001617:beta-Glucosidase