Assignment[sup 1] of the mouse Extl1 gene to the distal part of chromosome 4 by in situ hybridization and radiation hybrid mapping.

Recently, a family of homologous genes was identified, comprising EXT1 on 8q23->q24 and EXT2 on 11p12->p11, both causing multiple exostoses, and three EXT-like genes mapped on 1p36.1, 1p12->p11 and 8p22->p12 respectively. Functional studies have revealed that the EXT genes and EXTL2 are involved in heparan sulfate biosynthesis, while EXTL3 is thought to encode a receptor for Reg-proteins. However, the function of EXTL1 still remains to be elucidated. Here, we describe the mapping of the mouse Extl1 gene to the distal part of mouse chromosome 4.