Hairy genes family in developing neural crest of Xenopus laevis

GUILLERMO VEGA LÓPEZ; MANUEL J. AYBAR

Giens

Congreso; 14th International Xenopus Conference; 2012

Organizing committee: Odile BRONCHAIN - Laurent KODJABACHIAN - Karine MASSÉ - Anne-Hélène MONSORO-BURQ - Muriel PERRON - Nicolas POLLET

In the formation of the neural crest (NC) several cell signaling pathways participate in its development. The Notch/Delta signaling pathway has been involved in the induction of the NC of Xenopus laevis. The Hairy family genes (Hairy1, Hairy2a and Hairy2b) have been postulated as direct targets of Notch/Delta signaling pathway in vertebrates and invertebrates. In this work we determined by  in vivo overexpression in embryos, by microinyeción mRNA of the inducible proteins and dominant negatives or antisense oligonucleotides, that Hairy genes are required for the induction and migration of NC. Blocking Hairy genes resulted in a decreased  expression of NC gene markers, as well as higher levels of apoptosis and inhibition of the development of tissues derived from the NC. Furthermore, the analysis using inducible transcriptional activator or repressor chimeric proteinsof Hairy genes, indicated that these genes function as transcriptional repressors during the NC induction process  Additionally, we examined the regulation of Hairy genes expression by different cell signaling pathways. Hairy genes were found to be down-regulated by BMP-Smad pathway, while having a positive regulation from Notch/Delta-Su(h) and Ihh-Gli3 cell signaling pathways. The results of this study showed that Hairy genes have unique characteristics that differentiate the functions previously described in other species, and that they are differentially required for the processes of early the NC development.