Saldivar, Jose R. and Sechrist, John W. and Krull, Catherine E. and Ruffins, Seth and Bronner, Marianne E. (1997) Dorsal hindbrain ablation results in rerouting of neural crest migration and changes in gene expression, but normal hyoid development. Development, 124 (14). pp. 2729-2739. ISSN 0950-1991 http://resolver.caltech.edu/CaltechAUTHORS:20120119-134915476
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Our previous studies have shown that hindbrain neural tube cells can regulate to form neural crest cells for a limited time after neural fold removal (Scherson, T., Serbedzija, G., Fraser, S. E. and Bronner-Fraser, M. (1993). Development 188, 1049-1061; Sechrist, J., Nieto, M. A., Zamanian, R. T. and Bronner-Fraser, M. (1995). Development 121, 4103-4115). In the present study, we ablated the dorsal hindbrain at later stages to examine possible alterations in migratory behavior and/or gene expression in neural crest populations rostral and caudal to the operated region. The results were compared with those obtained by misdirecting neural crest cells via rhombomere rotation. Following surgical ablation of dorsal r5 and r6 prior to the 10 somite stage, r4 neural crest cells migrate along normal pathways toward the second branchial arch. Similarly, r7 neural crest cells migrate primarily to the fourth branchial arch. When analogous ablations are performed at the 10- 12 somite stage, however, a marked increase in the numbers of DiI/Hoxa-3-positive cells from r7 are observed within the third branchial arch. In addition, some DiI-labeled r4 cells migrate into the depleted hindbrain region and the third branchial arch. During their migration, a subset of these r4 cells up-regulate Hoxa-3, a transcript they do not normally express. Krox20 transcript levels were augmented after ablation in a population of neural crest cells migrating from r4, caudal r3 and rostral r3. Long-term survivors of bilateral ablations possess normal neural crest-derived cartilage of the hyoid complex, suggesting that misrouted r4 and r7 cells contribute to cranial derivatives appropriate for their new location. In contrast, misdirecting of the neural crest by rostrocaudal rotation of r4 through r6 results in a reduction of Hoxa-3 expression in the third branchial arch and corresponding deficits in third arch-derived structures of the hyoid apparatus. These results demonstrate that neural crest/tube progenitors in the hindbrain can compensate by altering migratory trajectories and patterns of gene expression when the adjacent neural crest is removed, but fail to compensate appropriately when the existing neural crest is misrouted by neural tube rotation.
|Additional Information:||© 1997 The Company of Biologists Limited. Accepted 1 May 1997. We thank Drs Scott Fraser, Mark Selleck and Carole LaBonne for critically reading the manuscript and Simone Lutolf, Katrin Wunnenberg-Stapleton, Roham Zamanian and Parisa Zarbafian for assistance with DiI-labeling, microsurgeries and cryosectioning and Drs Robb Krumlauf and David Wilkinson for providing cDNA probes. This work was supported by NS57315 and HD15527 to M. B. F. and minority supplement on DE10066 for J. R. S.|
|Subject Keywords:||neural crest; hindbrain; Hox genes; chicken; cell migration|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||19 Jan 2012 22:41|
|Last Modified:||26 Dec 2012 14:43|
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