The transcription factor Sox9 is required for cranial neural crest development inXenopus

Abstract

The SOX family of transcription factors has been implicated in cell fate specification during embryogenesis. One member of this family, Sox9, has been shown to regulate both chondrogenesis and sex determination in the mouse embryo. Heterozygous mutations in Sox9 result in Campomelic Dysplasia (CD), a lethal human disorder characterized by autosomal XY sex reversal, severe skeletal malformations and several craniofacial defects. Sox9 is also expressed in neural crest progenitors but very little is known about the function of Sox9 in the neural crest. We have cloned the Xenopus homolog of the Sox9 gene. It is expressed maternally and accumulates shortly after gastrulation at the lateral edges of the neural plate, in the neural crest-forming region. As development proceeds, Sox9 expression persists in migrating cranial crest cells as they populate the pharyngeal arches. Depletion of Sox9 protein in developing embryos, using morpholino antisense oligos, causes a dramatic loss of neural crest progenitors and an expansion of the neural plate. Later during embryogenesis, morpholino-treated embryos have a specific loss or reduction of neural crest-derived skeletal elements, mimicking one aspect of the craniofacial defects observed in CD patients. We propose that Sox9 is an essential component of the regulatory pathway that leads to cranial neural crest formation.

Epithelial–mesenchymal transition and its transcription factors

“…The TF, SOX9, was found to be required for neural crest development [ 162 , 163 ]. Moreover, it was also shown to be expressed during hepatic stellate cell activation and caused type I Collagen production in presence of TGFβ [ 164 ].…”

An efficient miRNA knockout approach using CRISPR-Cas9 in Xenopus

“…2 E’). These phenotypes suggest a possible role for miR-196a and miR-219 in NC development ( Collazo et al., 1993 ; Lukoseviciute et al., 2018 ; Petratou et al., 2021 ; Scerbo and Monsoro-Burq, 2020 ; Spokony et al., 2002 ).…”

16p12.1 Deletion Orthologs are Expressed in Motile Neural Crest Cells and are Important for Regulating Craniofacial Development in Xenopus laevis

“…The process of NCC induction and specification is complex and requires a specific level of signaling by the BMP, Wnt, FGF, RA, Shh, and Notch/Delta pathways to establish a gene regulatory network that is crucial for determining NCC identity ( Villanueva et al, 2002 ; Monsoro-Burq et al, 2003 ; Wu et al, 2005 ; Theveneau and Mayor, 2012 ; Pla and Monsoro-Burq, 2018 ; Rogers and Nie, 2018 ; Prasad et al, 2019 ). During the early steps of NCC formation, these morphogen pathways work in concert with various NCC transcription factors (TFs) such as snai1 , snai2/slug , sox9 , and twist , to establish the neural plate border, regulate NCC specification, and subsequent NCC migration ( Aybar et al, 2003 ; del Barrio and Nieto, 2002 ; LaBonne and Bronner-Fraser, 1998 , 2000 ; Pla and Monsoro-Burq, 2018 ; Rogers and Nie, 2018 ; Spokony et al, 2002 ). As shown in the previous sections, we found that partial depletion of several 16p12.1-affected genes significantly impacted twist expression patterns and NCC migration in the PAs, and that these defects were not due to changes in NCC proliferation rates.…”