EXPRESSION OF LIM-DOMAIN BINDING-PROTEIN (LDB) GENES DURING ZEBRAFISHEMBRYOGENESIS

LIM homeodomain proteins are developmental regulators whose functions depend on synergism with LIM domain binding proteins (Ldb proteins). W e have isolated four members of the [db gene family from the zebrafish , Danio rerio. Ldb1, Ldb2 and Ldb3 share 95%, 73% and 62% amino acid i dentity with mouse Ldb1, respectively. In overlay assays, Ldb proteins bind LIM homeodomain proteins and LMO1, but not zyxin or MLP. Whole m ount in situ hybridization showed that zebrafish ldb1 is expressed ubi quitously from gastrulation onward. Ldb2 is ubiquitous at gastrulation , and later is found in many but not all tissues, especially the anter ior central nervous system (CNS) and vasculature. Ldb3 mRNA was expres sed primarily in the anterior CNS. (C) 1998 Published by Elsevier Scie nce ireland Ltd.