GENOMIC STRUCTURE AND CHROMOSOMAL LOCALIZATION OF THE MOUSE LIM HOMEOBOX GENE LHX3/

We have previously cloned the murine Lhx3 cDNA that encodes a predicte d protein containing two tandemly repeated LIM domains and a homeodoma in. Early expression of Lhx3 in oral ectoderm that is committed to con tribute to the anterior and intermediate lobes of the pituitary and it s perseverance in the adult gland strongly suggest an involvement of t he gene in mediating and maintaining the differentiation program of th is important endocrine system. Additional functions are suggested by t he fact that Lhx3 is also expressed bilaterally along the spinal cord and the hindbrain at early stages of mouse development. Here we report the structural organization and chromosomal localization of the Lhx3 gene. The gene is composed of six exons and five introns. Two differen t exons, Ia and Ib, appear to be alternatively spliced to exon II. The first LIM domain is encoded by exon II and the second by exon III. Th e homeobox is shared by exons IV and V. We have mapped Lhx3 to the pro ximal region of mouse chromosome 2 in a region that shares homology wi th human chromosomes 9q and 10p. (C) 1995 Academic Press, Inc.