The T genes in embryogenesis.

Since its identification in 1927, the mouse T (Brachyury) locus has been implicated in mesoderm formation and notochord differentiation. Recent work has demonstrated that this gene encodes a putative transcription factor expressed specifically in nascent mesoderm and in the differentiating notochord. Homologous genes have been cloned from the frog Xenopus laevis, the zebrafish Brachydanio rerio and the ascidian Halocynthia roretzi. The T gene is an important tool for elucidating mesoderman and embryonic pattern formation.