Requirement of miR-145 in zebrafish neural crest development.

STEEMAN, TOMÁS J.; CALCATERRA NORA; ANDREA M.J. WEINER

Buenos Aires

Congreso; LASDB Meeting 2019; 2019

LASDB

The neural crest is a transient and multipotent cell population that gives rise to a diverse cell lineage. A complex gene regulatory network controlling the specification, delamination, migration, and differentiation of this cell type has been thoroughly described. However, the role of post-transcriptional factors, such as miRNAs, has not been deeply characterized yet.  Sox9 is required for determination of the chondrogenic cell lineage in the cranial neural crest. Its expression is regulated by miR-145 during chondrogenic differentiation in human and mouse cultured cells, but scant information exists regarding the role of this miRNA during embryogenesis. Metformin treatment of zebrafish embryos caused the overexpression of miR-145. The goal of this work was to assess the function of miR-145 during the neural crest development in zebrafish. In-silico analysis of the sox9b 3?UTR showed the presence of one miR-145 binding site. Furthermore, the analysis of the miR-145 promoter revealed the presence of multiple putative binding sites for SOX9, suggesting a regulatory feedback loop. Overexpression of miR-145 or metformin treatment in zebrafish embryos caused aberrant craniofacial development, low melanin levels, and elevated apoptosis throughout the embryo. Besides, abnormal expression of sox9b, sox10, and dct was measured by RT-qPCR.  In order to assess the role of miR-145 in the neural crest gene regulatory network, two knock-out mutant lines were generated using CRISPR/Cas9 technology.