The diversity of C-type lectins in the genome of a basal metazoan, Nematostella vectensis.

C-type lectins (CTLs) are involved in cell-cell adhesion, recognition, and innate immunity in higher vertebrates, but little is known about CTLs in basal metazoans. The recent sequencing of the cnidarian Nematostella vectensis genome allowed us to explore the CTL-like gene family at the base of metazoan evolution. Sixty-seven predicted CTLs, with a total of 92 putative C-type lectin domains (CTLDs), were classified according to number of CTLDs present and their association with other protein domains in the CTL. Conserved residues in the glycan-binding pocket suggest that approximately half of the CTLDs retain glycan-binding function. Phylogenetic analysis of N. vectensis CTLDs with respect to other model invertebrates and humans indicates N. vectensis CTLD sequences more closely resemble vertebrate CTLDs. This study provides a N. vectensis CTL database that can be used for further research on the evolution of cnidarian CTLs and the role of CTLs in cnidarian innate immunity.