Sialic Acid Binding Ig Like Lectin 6 (SIGLEC6)

The deduced 442-amino acid CD33L protein contains a signal peptide, an N-terminal Ig-like V-domain, and 2 adjacent Ig C2-like domains, followed by a transmembrane region and a cytoplasmic tail. Based on its predicted structure, the authors stated that CD33L belongs to the Ig superfamily and is likely a novel member of the sialoadhesin subfamily. Compared to the original cDNA, this cDNA contains a 176-bp deletion in the coding sequence, resulting in a predicted 342-amino acid protein lacking the transmembrane and cytoplasmic regions. By RT-PCR of placenta RNA, the authors detected both transcripts, although the transcript encoding the membrane-bound isoform, CD33L1, was considerably more abundant.CD33L expression only in the placenta; transcripts of 4 distinct sizes were found, including 1 that was differentially polyadenylated.