Paraxis expression in neural crest cells migration during post-somitic Xenopus laevis embryos

LUQUE M.E.; SÁNCHEZ R.S.; MÓNACO M.E.; SÁNCHEZ S.S.

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Anual Meeting Sociedad Argentina de Investigacion en Bioquímica y Biología Molecular; 2007

Sociedad Argentina de Investigacion en Bioquímica y Biología Molecular

During morphogenesis somite and neural crest (NC) ontogeny are two important processes of vertebrates. In embryogenesis the paraxial mesoderm (PM) becomes segmented and gives rise to the somites. Paraxis is a bHLH-transcription factor which is expressed in PM and then in the somites of mouse, chicken and amphibian embryos. Later its expression declines after sclerotome formation. In Xenopus laevis, paraxis is also expressed in the neural tube and the head mesoderm. We analyzed by RT-PCR, whole mount in situ hybridization and histology the paraxis expression in post-somitic stages of Xenopus laevis embryos. Several markers were used in order to determine the different embryo regions.  In the present study for a first time we observed the expression of paraxis transcription factor associated with migrating NC cells, under cranial, cardiac and trunk pathways. In relation to cranial migration stream paraxis is expressed in the craniofacial mesenchyme, otic vesicle and pharyngeal arches. Paraxis is also expressed in aortic arch arteries and the septum between the aorta and pulmonary artery corresponding to the cardiac NC. In trunk NC cells which migrate to the dorsal fin along the dorsal lateral pathway to form melanocytes, paraxis is expressed. Our results suggest that paraxis transcription factor may comprise part of regulatory cascade involved in the migration of NC cells.