Cloning of the cDNA for a New Member of the Immunoglobulin Superfamily (ISLR) Containing Leucine-Rich Repeat (LRR)

We isolated cDNAs for a novel protein with a calculated molecular mass of 46 kDa, containing a leucine-rich repeat (LRR) with conserved flanking sequences and a C2-type immunoglobulin (Ig)-like domain. This novel protein was considered to be a new member of the Ig superfamily and was named ISLR (immunoglobulin superfamily containing LRR). These domains are known to be important for protein–protein interaction or cell adhesion, and therefore it is possible that the novel protein ISLR may also interact with other proteins or cells. Northern blot analysis showed the presence of a 2.4-kb transcript in various human tissues including retina, heart, skeletal muscle, prostate, ovary, small intestine, thyroid, adrenal cortex, testis, stomach, and spinal cord as well as fetal lung and fetal kidney. The ISLR gene was mapped on human chromosome 15q23–q24 by fluorescencein situhybridization.