CDNA CLONING, EXPRESSION, AND CHROMOSOMAL LOCALIZATION OF A HUMAN UDP-GALNAC-POLYPEPTIDE, N-ACETYLGALACTOSAMINYLTRANSFERASE

Oligonucleotide primers derived from the cDNA encoding a full-length b ovine UDP-GalNAc:polypeptide, N-acetylgalactosaminyltransferase (GalNA c-transferase) [Homa, .L., Hollander, T., Lehman, D.J., Thomsen, D.R., and Elhammer, A.P, (1993) J. BioL. Chem. 268, 12609-12616], were used for PCR to isolate sequences encoding a homologous enzyme from human salivary gland cDNA. Comparison of the human and bovine nucleotide seq uences reveals 94.8% sequence identity in their coding regions and 87% identity in their 3-untranslated regions. The translation of the huma n GalNAc-transferase coding region predicts an amino acid sequence whi ch is nearly identical (99.6%) to that of the bovine counterpart; ther e are five conservative and one non-conservative amino acid substituti ons between the two enzymes. Expression of the bovine and human cDNAs in the insect cell line, Sf9, resulted in the synthesis of proteins wh ich appeared identical on SDS-PAGE and which had similar enzymatic pro perties. Screening of a somatic cell human/rodent hybrid panel with a probe derived from the human GalNAc-transferase cDNA sequence indicate d that the human GalNAc-transferase gene is localized to chromosome 18 .