2000 Volume 127 Issue 5 Pages 845-854
cDNA clones encoding mouse GalNAc α2, 6-sialyltransferase (ST 6 GalNAc I) were isolated from a mouse submaxillary gland cDNA library. The deduced amino acid sequence of cDNA clones is 526 amino acids in length and has highly conserved motifs among sialyl transferases, sialyl motifs L, S, and VS. The expressed recombinant enzyme exhibited similar substrate specificity to chicken ST 6 GalNAc I. The mouse ST 6 GalNAc I gene was expressed in submaxillary gland, mammary gland, colon, and spleen. The mouse ST 6 GalNAc I gene was also cloned from a mouse genomic library, which was divided into 9 exons spanning over 8 kilobases of genomic DNA. The genomic structure of the mouse ST 6 GalNAc I gene was similar to that of the mouse ST 6 GalNAc II gene. Unlike the ST 6 GalNAc II gene, however, which has a housekeeping gene-like promoter with GC-rich sequences, the ST 6 GalNAc I gene has two promoters and they do not contain GC-rich sequences but contain putative binding sites for tumor-associated transcription factors such as c-Myb, c-Myc/Max, and c-Ets. Analysis of the 5'-RACE PCR products suggested that the mouse ST 6 GalNAc I gene expression is regulated by these two promoters in tissue-specific manners.
