| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2176729 | Developmental Cell | 2014 | 17 Pages |
•Early limb-innervation programs are induced and constrained by diverse Hox inputs•Hoxc9 restricts the position of limb-innervating motor neurons to the correct site•Selective Hoxc9 protein function emerged as vertebrates acquired paired appendages•Hoxc9 gene expression contributes to evolutionary diversification of neuronal pattern
SummaryThe emergence of limb-driven locomotor behaviors was a key event in the evolution of vertebrates and fostered the transition from aquatic to terrestrial life. We show that the generation of limb-projecting lateral motor column (LMC) neurons in mice relies on a transcriptional autoregulatory module initiated via transient activity of multiple genes within the HoxA and HoxC clusters. Repression of this module at thoracic levels restricts expression of LMC determinants, thus dictating LMC position relative to the limbs. This suppression is mediated by a key regulatory domain that is specifically found in the Hoxc9 proteins of appendage-bearing vertebrates. The profile of Hoxc9 expression inversely correlates with LMC position in land vertebrates and likely accounts for the absence of LMC neurons in limbless species such as snakes. Thus, modulation of both Hoxc9 protein function and Hoxc9 gene expression likely contributed to evolutionary transitions between undulatory and ambulatory motor circuit connectivity programs.PaperClip To listen to this audio, enable JavaScript on your browser. However, you can download and play the audio by clicking on the icon belowHelp with MP3 filesOptionsDownload audio (5987 K)
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