Cpeb1 expression is post-transcriptionally regulated by AUF1, CPEB1, and microRNAs.

Cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates the translation of numerous mRNAs. We previously showed that AU-rich binding factor 1 (AUF1) regulates Cpeb1 expression through the 3' untranslated region (3'UTR). To investigate the molecular basis of the regulatory potential of the Cpeb1 3'UTR, here we performed reporter analyses that examined expression levels of Gfp reporter mRNA containing the Cpeb1 3'UTR. Our findings indicate that CPEB1 represses the translation of Cpeb1 mRNA and that miR-145a-5p and let-7b-5p are involved in the reduction in Cpeb1 expression in the absence of AUF1. These results suggest that Cpeb1 expression is post-transcriptionally regulated by AUF1, CPEB1, and microRNAs.