HH cells are heterozygous for a point mutation in C2GnT-I. (A) Partial sequence alignment of C2GnT-I cDNA from HH cells (underlined) with human C2GnT-I cDNA sequence derived from NCBI Nucleotide Database, accession number BC074885. The 692 C/G mutation is indicated in bold (arrow). Sequences were aligned using NCBI Blast 2 sequences. (B) Chromatogram from the C2GnT-I cDNA forward strand sequence from HH cells, demonstrating the 692 C/G mutation. The asterisk (*) denotes overlapping peaks, indicating that the cells are heterozygous for the mutation. (C) Partial amino acid sequence alignment of the predicted C2GnT-I nucleotide sequences from HH cells, translated with the ExPASy Translate Tool. The 692 C/G mutation results in a substitution of Cys for Ser at position 158 (arrow). Boxes indicate Cys residues that are highly conserved in the β1,6-N-acetylglucosaminyltransferase family.