High impact information on Dbx1

• Shh signaling is sufficient to induce Dbx cells and V0 and V1 neurons but is not required for their generation in vitro or in vivo [1].
• Further, Hh signaling extends into the dorsal half of the spinal cord including the intermediate Dbx expression domain [2].
• Together, these findings identify Dbx1-dependent interneurons as key components of the spinal locomotor circuits that control stepping movements in mammals [3].
• We show a discrete subset of commissural spinal interneurons, whose fate is controlled by the activity of the homeobox gene Dbx1, has a critical role in controlling the left-right alternation of motor neurons innervating hindlimb muscles [3].
• V0 and V1 interneurons derive from adjacent progenitor domains that are distinguished by expression of the homeodomain proteins Dbx1 and Dbx2 [4].

Biological context of Dbx1

• In Dbx1 mutant mice, neural progenitors fail to generate V0 neurons and instead give rise to interneurons that express many characteristics of V1 neurons-their transcription factor profile, neurotransmitter phenotype, migratory pattern, and aspects of their axonal trajectory [4].
• We show that a Dbx1 enhancer drives tau-lacZ expression in a subpopulation of commissural axons and, using a reporter line generated from this construct, as well as DiI tracing, we find that commissural axons projected to the ventral midline in Gli2(-/-) embryos [5].
• Dbx1 is strongly and specifically expressed in progenitor cells (ventricular zone) of the ventral pallium during early embryonic development, but there is no signal of this gene in the rest of the pallium nor the subpallium [6].
• The Dbx homeodomain shows highest sequence homology to Drosophila H2.0 and chicken CHox E [7].
• The expression of the transgene closely resembles that of the Dbx gene with minor, but interesting differences [8].

Anatomical context of Dbx1

• Control of interneuron fate in the developing spinal cord by the progenitor homeodomain protein Dbx1 [4].
• Dbx1 mutant mice lacking these ventral interneurons exhibit an increased incidence of cobursting between left and right flexor/extensor motor neurons during drug-induced locomotion [3].
• We found that a subpopulation of oligodendrocytes is generated from the Dbx1-expressing domain of the VZ, spanning the dorsoventral midline [9].
• Dbx may act to specify subsets of neuroblasts during the development of the central nervous system [7].
• Dbx transcripts are detected within a region of the prospective cerebral cortex of the midgestation telencephalon [7].

Other interactions of Dbx1

• No recombination was observed between Dbx and Odc-rs6, indicating that Dbx lies approximately 25 cM distal to the Chr 7 centromere in a region that has conserved linkage relationships with regions of human Chrs 11 and 19 [10].
• Members of several classes have been isolated, including the Msx genes, two Dlx genes, and the Dbx, MHox, Mox2A genes [11].

Analytical, diagnostic and therapeutic context of Dbx1

• In situ hybridization analyses indicate that Dbx is expressed exclusively within the embryonic central nervous system in a highly restricted manner [7].

References