Molecular basis of differential target regulation by miR-96 and miR-182: the Glypican-3 as a model.
Besides the fact that miR-96 and miR-182 belong to the miR-182/183 cluster, their seed region (UUGGCA, nucleotides 2-7) is identical suggesting potential common properties in mRNA target recognition and cellular functions. Here, we used the mRNA encoding Glypican-3, a heparan-sulfate proteoglycan, as a model target as its short 3' untranslated region is predicted to contain one miR-96/182 site, and assessed whether it is post-transcriptionally regulated by these two microRNAs. We found that miR-96 downregulated GPC3 expression by targeting its mRNA 3'-untranslated region and interacting with the predicted site. This downregulatory effect was due to an increased mRNA degradation and depended on Argonaute-2. Despite its seed similarity with miR-96, miR-182 was unable to regulate GPC3. This differential regulation was confirmed on two other targets, FOXO1 and FN1. By site-directed mutagenesis, we demonstrated that the miRNA nucleotide 8, immediately downstream the UUGGCA seed, plays a critical role in target recognition by miR-96 and miR-182. Our data suggest that because of a base difference at miRNA position 8, these two microRNAs control a completely different set of genes and therefore are functionally independent.
Université Bordeaux Segalen, Bordeaux, F-33076 Bordeaux, France.
Sandra
S
Jalvy-Delvaille
Marion
M
Maurel
Vanessa
V
Majo
Nathalie
N
Pierre
Sandrine
S
Chabas
Chantal
C
Combe
Jean
J
Rosenbaum
Francis
F
Sagliocco
Christophe F
CF
Grosset
D020413:3' Untranslated Regions; D020029:Base Pairing; D001483:Base Sequence; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D053673:Glypicans / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000737:chemistry* / Q000502:physiology; D008969:Molecular Sequence Data
D020413:3' Untranslated Regions; D053673:Glypicans; C541492:MIRN96 microRNA, human; D035683:MicroRNAs; C538984:Mirn182 microRNA, human