CPEB2, CPEB3 and CPEB4 are coordinately regulated by miRNAs recognizing conserved binding sites in paralog positions of their 3'-UTRs.
The cytoplasmic polyadenylation element binding-protein (CPEB) is an RNA-binding protein that participates in translational control. CPEB2, CPEB3 and CPEB4 are paralog proteins very similar among themselves referred as the CPEB2 subfamily. To gain insight into common mechanisms of regulation of the CPEB2 subfamily transcripts, we looked for putative cis-acting elements present in the 3'-UTRs of the three paralogs. We found different families of miRNAs predicted to target all subfamily members. Most predicted target sites for these families are located in paralog positions suggesting that these putative regulatory motifs were already present in the ancestral gene. We validated target sites for miR-92 and miR-26 in the three paralogs using mutagenesis of miRNA-binding sites in reporter constructs combined with over-expression and depletion of miRNAs. Both miR-92 and miR-26 induced a decrease in Luciferase activity associated to a reduction in mRNA levels of the reporter constructs. We also showed that the endogenous miRNAs co-regulate CPEB2, CPEB3 and CPEB4 transcripts, supporting our hypothesis that these genes have a common regulatory mechanism mediated by miRNAs. We also suggest that the ancestral pattern of miRNA-binding motifs was maintained throughout the generation of highly conserved elements in each of the 3'-UTRs.
Morgan
Marcos
M
International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy. muro@icgeb.org
Iaconcig
Alessandra
A
Muro
Andrés Fernando
AF
D020413:3' Untranslated Regions; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017124:Conserved Sequence; D005786:Gene Expression Regulation; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D008969:Molecular Sequence Data; D026723:Polyadenylation; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism
D020413:3' Untranslated Regions; D035683:MicroRNAs; D016601:RNA-Binding Proteins; C554938:CPEB2 protein, human; C513866:CPEB3 protein, human; C554939:CPEB4 protein, human; C546783:MIRN192 microRNA, human; C528163:MIRN26 microRNA, human