Isthmin 2 (ISM2)

Most ESTs corresponded to a transcript lacking exon 2 and encoding a 571-amino acid isoform, and an alternative 292-amino acid isoform lacking exons 2 and 5 was also identified. ISM2 contains a 26-amino acid N-terminal hydrophobic signal peptide, 17 putative glycosylation sites, a central region with a cluster of negatively charged residues, a TSR domain with a WSXW heparin-binding motif, and a C-terminal adhesion-associated domain found in MUC4 and other proteins (AMOP). RT-PCR analysis of human tissues demonstrated high expression in placenta and moderate expression in pancreas, kidney, and brain and low expression in heart, liver, lung, and skeletal muscle. Analysis with exon-flanking PCR primers supported the presence of tissue-specific alternatively spliced transcripts.