Murine alpha-N-acetylgalactosaminidase: isolation and expression of a full-length cDNA and genomic organization: further evidence of an alpha-galactosidase gene family.
Recent characterization of the human sequences encoding two lysosomal hydrolases, alpha-galactosidase A (alpha-Gal A) and alpha-N-acetylgalactosaminidase (alpha-GalNAc) revealed that these two enzymes with distinct enzymatic activities shared about 50% overall amino acid identity and that their genomic sequences had a conserved common gene structure. These findings suggested that these genes, which are located on different chromosomes, arose by duplication and divergence from a common ancestral gene. To further compare this alpha-galactosidase gene family, the murine alpha-GalNAc cDNA and genomic sequences were isolated and characterized. The full-length cDNA contained an open-reading frame of 1245 bp encoding a 415 amino acid polypeptide and had 5' and 3' untranslated regions of 94 and 333 bp, respectively. The coding region had 81% nucleotide and 81.9% amino acid identities with those of the corresponding human alpha-GalNAc sequence. Northern analysis revealed a single transcript of approximately 1.9 kb. The functional integrity of the cDNA was demonstrated by transient expression in COS-1 cells. The murine alpha-GalNAc genomic sequence spanned approximately 9 kb and was identical in structure with the human alpha-GalNAc gene with eight introns interrupting the coding sequence at identical positions. In addition, the deduced amino acid sequence of the murine alpha-GalNAc gene was highly homologous with alpha-GalNAc and alpha-Gal A genes from other species providing further support for a common evolutionary ancestor of the alpha-galactosidase gene family. The availability of the murine gene will permit additional evolutionary comparisons, structure/function analyses, and the generation of mice with alpha-GalNAc deficiency by gene targeting.
Wang
A M
AM
Department of Human Genetics, Mount Sinai School of Medicine, New York, New York, 10029, USA.
Ioannou
Y A
YA
Zeidner
K M
KM
Desnick
R J
RJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics* / Q000302:isolation & purification; D019143:Evolution, Molecular; D015870:Gene Expression; D005796:Genes; D016678:Genome; D006596:Hexosaminidases / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D000519:alpha-Galactosidase / Q000235:genetics*; D048809:alpha-N-Acetylgalactosaminidase
D017931:DNA Primers; D018076:DNA, Complementary; D006596:Hexosaminidases; D000519:alpha-Galactosidase; C482722:NAGA protein, human; D048809:alpha-N-Acetylgalactosaminidase