Epigenetic-microRNA regulation to edge the neural and neural plate border

ALATA JIMENEZ, NAGIF; SANCHEZ-VASQUEZ, E.; STROBL MAZZULLA, P.H.

Simposio; Latin american society of developmental biology; 2019

The neural plateborder (NPB) includes a group of embryonic progenitors, delimited closely bythe neural plate (NP) and the epidermis, where the neural crest cells (NCC) areinduced. Although the progenitors that contribute to both tissues have the sameorigin, the ectoderm, there are few studies that demonstrated the molecularmechanisms of how their territorial limits are defined. By in silico analysiswe found that the 3'UTRs of Prdm1 and Tfap2a, two of main transcription factorsinvolved in the early induction of the NPB, have highly conserved binding sitesfor miR137. Our expression studies by in situ hybridization in chicken embryosshowed a clear territorial exclusion between tissues where Prdm1 and Tfap2a(NPB) and miR137 (NP) are expressed. In vivo loss- and gain-of-functionexperiments of miR137 showed an increase and decrease in their expressionterritories. It has been described that miR137 is repressed by DNA methylationduring neural differentiation. However, the analyzes of miR137 regulatoryregions by using bisulfite sequencing evidenced no differences in the percentageof CpG methylation from NPB and NP samples. Interestingly, we were able todetermine a greater abundance in non-CpG methylation in the NPB with respect toNP. Taken together, our results reveal  that non-canonical DNA methylations would beresponsible for regulating spatially the expression of miR137 which is requiredduring the edging of the NPB territory.