Ladybird (Lbx) homeodomain transcription factors function in neural and muscle 
development--roles conserved from Drosophila to vertebrates. Lbx expression in 
mice specifies neural cell types, including dorsally located interneurons and 
association neurons, within the neural tube. Little, however, is known about the 
regulation of vertebrate lbx family genes. Here we describe the expression 
pattern of three zebrafish ladybird genes via mRNA in situ hybridization. 
Zebrafish lbx genes are expressed in distinct but overlapping regions within the 
developing neural tube, with strong expression within the hindbrain and spinal 
cord. The Hox family of transcription factors, in cooperation with cofactors 
such as Pbx and Meis, regulate hindbrain segmentation during embryogenesis. We 
have identified a novel regulatory interaction in which lbx1 genes are strongly 
downregulated in Pbx-depleted embryos. Further, we have produced a transgenic 
zebrafish line expressing dTomato and EGFP under the control of an lbx1b 
enhancer--a useful tool to acertain neuron location, migration, and morphology. 
Using this transgenic strain, we have identified a minimal neural lbx1b enhancer 
that contains key regulatory elements for expression of this transcription 
factor.