Evidence that GRIP, a PDZ-domain protein which is expressed in the embryonic forebrain, co-activates transcription with DLX homeodomain proteins.

The DLX homeodomain proteins control development of the basal ganglia and branchial arches. To identify co-factors that regulate DLX function we utilized the yeast two-hybrid assay, and found a DLX interacting protein (DIP2) which binds to the N-terminal region of DLX2 via a PDZ domain. DIP2 appears to be an alternatively spliced form of GRIP1, a protein known to bind AMPA glutamate receptors via PDZ domains.

Cloning and developmental expression of a zebrafish meis2 homeobox gene.

We show here that a zebrafish meis2 gene homolog has a dynamic expression pattern in the developing mesoderm and central nervous system. Meis family homeodomain proteins are known to act as cofactors with other homeodomain proteins. We find expression of meis2.

Distal-less-related homeobox genes of vertebrates: evolution, function, and regulation.

Homeobox genes of the Distal-less family have been identified in virtually all metazoan groups where they play roles in the ontogeny of these animals. The vertebrate Distal-less related genes (Dlx genes) are thought to have arisen as a result of a tandem gene duplication event followed by a number of larger genomic scale duplications and thus represent an interesting model with which to study the evolution of clustered gene families. Dlx genes are involved in the development of the forebrain, branchial arches, sensory organs, and limbs.

Differential expression of orthologous Dlx genes in zebrafish and mice: implications for the evolution of the Dlx homeobox gene family.

Dlx homeobox genes of vertebrates are often organised as physically linked pairs in which the two genes are transcribed convergently (tail-to-tail arrangement). Three such Dlx pairs have been found in mouse, human, and zebrafish and are thought to have originated from the duplication of an ancestral gene pair. These pairs include Dlx1/Dlx2, Dlx7/Dlx3, and Dlx6/Dlx5 (the zebrafish orthologue of Dlx5 is named dlx4).

A highly conserved enhancer in the Dlx5/Dlx6 intergenic region is the site of cross-regulatory interactions between Dlx genes in the embryonic forebrain.

Four Dlx homeobox genes, Dlx1, Dlx2, Dlx5, and Dlx6 are expressed in the same primordia of the mouse forebrain with temporally overlapping patterns. The four genes are organized as two tail-to-tail pairs, Dlx1/Dlx2 and Dlx5/Dlx6, a genomic arrangement conserved in distantly related vertebrates like zebrafish. The Dlx5/Dlx6 intergenic region contains two sequences of a few hundred base pairs, remarkably well conserved between mouse and zebrafish.