Hox transcription factors influence motoneuron identity through the integrated actions of both homeodomain and non-homeodomain regions
Article first published online: 12 MAR 2012
Copyright © 2012 Wiley-Liss, Inc.
Volume 241, Issue 4, pages 718–731, April 2012
How to Cite
Misra, M., Sours, E. and Lance-Jones, C. (2012), Hox transcription factors influence motoneuron identity through the integrated actions of both homeodomain and non-homeodomain regions. Dev. Dyn., 241: 718–731. doi: 10.1002/dvdy.23763
- Issue published online: 12 MAR 2012
- Article first published online: 12 MAR 2012
- Accepted manuscript online: 21 FEB 2012 12:00AM EST
- Manuscript Accepted: 13 FEB 2012
- National Institutes of Health. Grant Number: R01-HD025676
- spinal cord;
- LIM genes;
- motoneuron development
Background: Hox transcription factors play a critical role in the specification of motoneuron subtypes within the spinal cord. Our previous work showed that two orthologous members of this family, Hoxd10 and Hoxd11, exert opposing effects on motoneuron development in the lumbosacral (LS) spinal cord of the embryonic chick: Hoxd10 promotes the development of lateral motoneuron subtypes that project to dorsal limb muscles, while Hoxd11 represses the development of lateral subtypes in favor of medial subtypes that innervate ventral limb muscles and axial muscles. The striking degree of homology between the DNA-binding homeodomains of Hoxd10 and Hoxd11 suggested that non-homeodomain regions mediate their divergent effects. In the present study, we investigate the relative contributions of homeodomain and non-homeodomain regions of Hoxd10 and Hoxd11 to motoneuron specification. Results: Using in ovo electroporation to express chimeric and mutant constructs in LS motoneurons, we find that both the homeodomain and non-homeodomain regions of Hoxd10 are necessary to specify lateral motoneurons. In contrast, non-homeodomain regions of Hoxd11 are sufficient to repress lateral motoneuron fates in favor of medial fates. Conclusions: Together, our data demonstrate that even closely related Hox orthologues rely on distinct combinations of homeodomain-dependent and -independent mechanisms to specify motoneuron identity. Developmental Dynamics 241:718–731, 2012. © 2012 Wiley Periodicals, Inc.