beta-1,4-N-Acetylgalactosaminyltransferase involved in ganglioside synthesis: cDNA sequence, expression, and chromosome mapping of the mouse gene.

beta-1,4-N-Acetylgalactosaminyltransferase (EC 2.4.1.92; GalNAc-T) is a glycosyltransferase involved in the synthesis of gangliosides GM2 and GD2 as well as glycolipid GA2. We have isolated and sequenced the mouse Gal-NAc-T cDNA, studied GalNAc-T mRNA expression in adult tissues and in embryos, and determined the chromosomal location of the GalNAc-T gene, Ggm2. In comparison with the human cDNA, the mouse sequence was 83 and 87% identical at the nucleic acid and amino acid levels, respectively. The GalNAc-T transcript was most abundantly expressed in brain, liver, lung, spleen, and testis among the eight adult tissues examined. Relatively high levels of expression were seen early in mouse development (7-day embryos) compared to later times (11, 15, and 17 days). The Ggm2 gene was mapped to a distal position on mouse chromosome 10 that is homologous to a portion of human chromosome 12.