Because numerous diseases affect the muscle and nervous systems, it is
important to identify and characterize genes that may play functional
roles in these tissues. Sequence analysis of a 106-kb region of human
Chromosome (Chr) 19q13.2 revealed a novel gene with homology to the N
euroendocrine-specific protein (NSP), and it has, therefore, been desi
gnated NSP-like 1 (Nspl1). We isolated the mouse homolog of this gene
and performed extensive expression analysis of both the mouse and huma
n genes. The mouse Nspl1 gene is alternatively spliced to produce two
major transcripts: a 2.1-kb mRNA that is expressed at highest levels i
n the brain, and a 1.2-kb transcript that is primarily expressed in mu
scle. The larger message contains 10 exons, whereas the smaller transc
ript contains 7 exons. The last 6 exons, which are present in both tra
nscripts, share significant amino acid sequence identity with the endo
plasmic reticulum-bound portion of NSP. Mouse and human Nspl1/NSPL1 ge
nes have expression patterns that are similar to that of the dystrophi
n gene. In addition, the putative regulatory domains of Nspl1 appear s
imilar in composition and distribution to the defined dystrophin regul
atory sequences.