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Mech Dev October 1, 2009; 126 (10): 804-16.

The role of miR-124a in early development of the Xenopus eye.

Qiu R , Liu K , Liu Y , Mo W , Flynt AS , Patton JG , Kar A , Wu JY , He R .

It has been reported that miR-124a is abundant in the central nervous system including the eye, and is related to neurogenesis in several species. However, the role of miR-124a in the eye remains unclear. In this study, we show that the expression of miR-124a in Xenopus laevis begins along the neural fold, including the protruding eye anlagen, at a low level at around stage 18; its expression level gradually increases in the neural tube and the eye as embryos develop into later stages and then maintains at a high level in eye to adult stages. Microinjection of a miR-124a precursor at the 8-cell stage leads to malformation of the optic nerve and optic cup, indicating the importance of maintaining low levels of miR-124a during early embryonic development. In addition, miR-124a overexpression markedly down regulates the expression of its predicted targets Lhx2, Hairy2, Gli3, NeuroD1 and Otx2 in/around the eye anlagen, and the interaction of miR-124a with the 3'' UTR of Lhx2 represses gene expression as shown by luciferase assays. Moreover, excess miR-124a inhibits cell proliferation in the eye of Xenopus embryos during retinogenesis. These results indicate that miR-124a acts as a post-transcriptional regulator in the genetic network controlling eye morphogenesis and neurogenesis. The mechanism of miR-124a''s early interaction with the genetic network may also persist in its later role in the maturing and adult eye and brain.

PubMed ID: 19703558
PMC ID: PMC4445405
Article link: Mech Dev
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: gli3 hes4 lhx2 neurod1 otx2 pax2 pax6 rax rho rho.2 rpe

Article Images: [+] show captions
References [+] :
Aboobaker, Drosophila microRNAs exhibit diverse spatial expression patterns during embryonic development. 2005, Pubmed