Human neuronal pentraxin II (NPTX2): conservation, genomic structure, and chromosomal localization.

We have previously identified a novel rat neuronal member of the pentraxin family (neuronal pentraxin) that may mediate the uptake of synaptic material and the presynaptic snake venom toxin, taipoxin. Here we report human cDNA and genomic sequences of a second neuronal pentraxin. This pentraxin, which we propose to name neuronal pentraxin II (NPII; gene symbol NPTX2), shows 54% amino acid identity to rat neuronal pentraxin (NPI) with 69% identity over the carboxyl-terminal half of NPI and is 88% identical to a newly identified sperm acrosomal pentraxin p50/apexin. Northern blot analysis reveals that NPII message is present in brain, testis, pancreas, liver, heart, and skeletal muscle, so, unlike NPI, NPII is not exclusively localized to neurons. Like NPI, NPII has potential N-linked glycosylation sites. The human NPII gene is 11 kb in length, contains four introns, and is localized to chromosome 7q21.3-q22.1. These data demonstrate the existence of a family of pentraxin proteins that are expressed in the brain and other tissues and that may play important roles in the uptake of extracellular material.