Developmental regulation of Tbx5 in zebrafish embryogenesis

T-box (rbs) genes constitute a large family of transcriptional regulators i nvolved in developmental patterning processes. In tetrapods, tbx5 has been implicated in specifying forelimb type identity. Here, we report the clonin g of the zebrafish tbx5.1 gene and characterise its expression during zebra fish embryogenesis and early larval development of wild type and mutant emb ryos that affect pectoral fin patterning. tbx5.1 is expressed during develo pment of the heart, the pectoral fins and the eye. Notably, its expression in the lateral plate mesoderm defines a single and continuous region of hea rt and pectoral fin precursor cells, and constitutes the earliest specific marker for pectoral fin development in the zebrafish. (C) 2000 Elsevier Sci ence Ireland Ltd. All rights reserved.