Specific expression of the Hox 1.3 homeo box gene in murine embryonic structures originating from or induced by the mesoderm.

The murine Hox 1.3 homeo box-containing gene is expressed largely in mesoderm-derived or mesoderm-induced embryonal structures, as evidenced by in situ hybridization techniques. Expression is spatially limited to the thoracic region, specifically to components of segmental origin such as embryonal ribs and vertebrae and their precursors such as the equivalent sclerotomes, somites and somatic condensations. In addition, expression can be found in parts of embryonal lung, stomach tissue, gut and kidney, tissues whose formation is based on induction of region-specific mesoderm, as well as in some ectoderm-derived tissues. The expression is temporally controlled for the transcripts and can only be detected while the thoracic structures are being formed (days 8-13), but not at day 18 of gestation when the embryo is mature. These data suggest a role of Hox 1.3 gene in the generation of tissues derived from or induced by the embryonal mesoderm.