Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Development December 1, 2000; 127 (24): 5367-78.

Ectopic Hoxa2 induction after neural crest migration results in homeosis of jaw elements in Xenopus.

Pasqualetti M , Ori M , Nardi I , Rijli FM .

Hox genes are required to pattern neural crest (NC) derived craniofacial and visceral skeletal structures. However, the temporal requirement of Hox patterning activity is not known. Here, we use an inducible system to establish Hoxa2 activity at distinct NC migratory stages in Xenopus embryos. We uncover stage-specific effects of Hoxa2 gain-of-function suggesting a multistep patterning process for hindbrain NC. Most interestingly, we show that Hoxa2 induction at postmigratory stages results in mirror image homeotic transformation of a subset of jaw elements, normally devoid of Hox expression, towards hyoid morphology. This is the reverse phenotype to that observed in the Hoxa2 knockout. These data demonstrate that the skeletal pattern of rhombomeric mandibular crest is not committed before migration and further implicate Hoxa2 as a true selector of hyoid fate. Moreover, the demonstration that the expression of Hoxa2 alone is sufficient to transform the upper jaw and its joint selectively may have implications for the evolution of jaws.

PubMed ID: 11076758
Article link: Development

Species referenced: Xenopus
Genes referenced: gal.2 gsc hoxa2 nkx3-1 nkx3-2 pbx1 snai2 tbx2 tfap2a znf469

Article Images: [+] show captions