The hamster gene for uridine diphosphate N-acetyl-D-glucosamine:dolichyl phosphate N-acetylglucosaminyl phosphoryl transferase (L-G1PT) was found to extend over 6.5 kb and to contain nine exons. The exons ranged in size from 63 to 214 bp, encoding the 408 amino acid protein. The introns ranged from 85 bp to 1.4 kb. Upstream 5' sequences included two possible TATA boxes, one possible CCAAT box and at least two potential GC boxes. Heterologous expression was successful in Schizosaccharomyces pombe, and resulted in cells that were tunicamycin resistant and had 12-fold more L-G1PT activity than wild-type cells. Antiserum prepared to a hydrophilic peptide (residues 300-320) of the L-G1PT protein reacted with a 35-36 kDa protein in membrane samples from Chinese hamster ovary (CHO) cells and S. pombe cells that had increased levels of L-G1PT activity. In both cases, antigenic peptide competed with the 35-36 kDa protein detected by the antiserum.