Characterization of the human TBX20 gene, a new member of the T-box gene family closely related to the Drosophila H15 gene

T-box transcription factors contain a novel type of DNA-binding domain, the T-box domain, and are encoded by an ancient gene family. Four T-box genes, omb, Trg, org-1, and H15, have been identified in Drosophila, whereas in m ammals the T-box gene family has expanded, and 12 human T-box genes have be en isolated. We have identified a new human T-box gene, TBX20, and its mous e homologue Tbx20 which are more closely related to the Drosophila H15 gene than to any known vertebrate gene. H15 expression in leg imaginal discs co rrelates with commitment to a ventral fate, implicating this gene in early patterning events. We find that TBX20 is expressed in the fetal heart, eye, and limb, and during embryogenesis in the mouse, Tbx20 is expressed in the developing heart, eye, ventral neural tube, and limbs, indicating a possib le role in regulating development of these tissues. The TBX20 gene maps to chromosome 7p14-p15. An association between TBX20 and loci for retinitis pi gmentosa, RP9, and blepharophimosis syndrome, BPES, have been excluded. (C) 2000 Academic Press.