Gli2 transcription factor participation in Xenopus laevis neural crest early development

SANTIAGO CERRIZUELA; MARIA BELEN PALACIO; GUILLERMO VEGA LÓPEZ; CELESTE TRIBULO; MANUEL J. AYBAR

Santos, Sao Paulo, Brasil

Congreso; VIII Meeting of Latin American Society for Developmental Biology; 2015

Latin American Society for Developmental Biology

Neural crestformation is one of the fundamental processes in the early embryonicdevelopment in vertebrates. The neural crest is a transient multipotent andmigratory cell population that differentiates and gives rise to a diversevariety of cellular types and tissues, such as cartilages, bone, connectivetissue, endocrine and pigmentary cells, neurons and glia. This differentiationpotential combined with a remarkable capacity of self-renewal support the factthat these cells have stem-cell properties. We have previously demonstratedthat Indian Hedgehog (Ihh) cell signaling pathway plays a key role in Xenopus laevis neural crest formation, specificationmaintenance and migration. Gli transcription factors are effectors of theHedgehog pathway and they act as a transcriptional activator or repressors indifferent situations or systems. In this work we established a detailed expressionpattern of gli2 transcripts atneurula stages by single and double in situ hybridization. We show that it isexpressed in the lateral neural plate border, which subsequently forms theneural crest. Overexpression of gli2 mRNAin segmenting embryos produced an increase in the expression of neural crestspecific markers both by in situ hybridization and RT-PCR in prospective neuralcrest explants. Gli2 overexpression also produced a reduction in the apoptosisof neural crest cells during neurula stages. The specific knock-out of gli2 function using an antisensemorpholino 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 stronglyaffected the formation of cartilages derived from the neural crest. Theepistatic analysis related gli2function with gli3 under the controlof Ihh activity for the neural crest early induction. Taken together our resultsindicate a key participation of gli2 inthe genetic network that controls the specification of the neural crest cells.FinancialSupport: CIUNT 26/D506, PICT2010-1224, PICT2013-1686 and PICT2013-0219