AUF1, an mRNA decay factor, has a discordant role in Cpeb1 expression

Cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates polyadenylation and subsequent translation of CPE-containing mRNAs involved in various physiological and pathological phenomena. Although the significance of CPEB1-mediated translational regulation has recently been reported, the detailed regulatory mechanism of Cpeb1 expression remains unclear. To elucidate the post-transcriptional regulatory mechanisms of Cpeb1 expression, we constructed reporter plasmids containing various deletions or mutations in the Cpeb1 mRNA 3′ untranslated region (3′UTR). We investigated their expression levels in Neuro2a neuroblastoma cells. We found that Cpeb1 expression is regulated through an AU-rich element in its 3′UTR. Furthermore, the mRNA decay factor AU-rich binding factor 1 (AUF1) regulates Cpeb1 expression, and knockdown of AUF1 upregulates Cpeb1 mRNA expression but results in a decrease in CPEB1 protein levels. These findings indicate that AUF1 has a discordant role in the expression of Cpeb1. •Cpeb1 3′UTR represses both Cpeb1 mRNA and protein expression levels.•Multiple elements in the Cpeb1 3′UTR are involved in Cpeb1 mRNA expression.•Serial AREs in the Cpeb1 3′UTR mediate Cpeb1 mRNA level.•Depletion of AUF1 increased the Cpeb1 mRNA levels, but reduced the protein levels.•Cpeb1 expression may be controlled by multimodal mechanisms through its 3′UTR.