gli2 transcription factor participation in Xenopus laevis neural crest early development

SANTIAGO CERRIZUELA; M. BELÉN PALACIO; GUILLERMO VEGA LÓPEZ; CELESTE TRÍBULO; MANUEL J. AYBAR

Santos

Congreso; 8th Meeting of the Latin American Society of Developmental Biology; 2015

Latin American Society for Developmental Biology (LASDB)

Neural crest formation is one of the fundamental processes in the early embryonic development in vertebrates. The neural crest is a transient multipotent and migratory cell population that differentiates and gives rise to a diverse variety of cellular types and tissues, such as cartilages, bone, connective tissue, endocrine and pigmentary cells, neurons and glia. This differentiation potential combined with a remarkable capacity of self-renewal support the fact that these cells have stem-cell properties. We have previously demonstrated that Indian Hedgehog (Ihh) cell signaling pathway plays a key role in Xenopus laevis neural crest formation, specification maintenance and migration. Gli transcription factors are effectors of the Hedgehog pathway and they act as a transcriptional activator or repressors in different situations or systems. In this work we established a detailed expression pattern of gli2 transcripts at neurula stages by single and double in situ hybridization. We show that it is expressed in the lateral neural plate border, which subsequently forms the neural crest. Overexpression of gli2 mRNA in segmenting embryos produced an increase in the expression of neural crest specific markers both by in situ hybridization and RT-PCR in prospective neural crest explants. Gli2 overexpression also produced a reduction in the apoptosis of neural crest cells during neurula stages. The specific knock-out of gli2 function using an antisense morpholino oligonucleotide produced a decrease in these specific gene markers foxd3, snail2, sox9 along with a decreased expression of the neural crest inducer pax3. Loss of gli2 function also affected neural crest cells migration, and strongly affected the formation of cartilages derived from the neural crest. The epistatic analysis related gli2 function with gli3 under the control of Ihh activity for the neural crest early induction. Taken together our results indicate a key participation of gli2 in the genetic network that controls the specification of the neural crest cells.