Although tumor protein D52 (TPD) family proteins were first identified nearly 20 years ago, their molecular regulatory mechanisms remain unclear. Therefore, we investigated the post-transcriptional regulation of TPD52 family genes. An RNA immunoprecipitation assay showed the potential binding ability of TPD52 family mRNAs to several RNA-binding proteins, and an RNA degradation assay revealed that TPD52 is subject to more prominent post-transcriptional regulation than TPD53 and 54. We subsequently focused on the 3'-untranslated region (3'-UTR) of TPD52 as a cis -acting element in post-transcriptional gene regulation. Several deletion mutants of the 3'-UTR of TPD52 mRNA were constructed and ligated to the 3' end of a reporter green fluorescence protein gene. RNA degradation assay revealed that a minimal cis -acting region, located in the 78-280 region of the 5'-proximal region of the 3'-UTR, stabilized the reporter mRNA. Biotin pull-down and RNA immunoprecipitation assays revealed specific binding of the region to T-cell intracellular antigen 1 (TIA-1) and TIA-1-related protein (TIAR). Knockdown of TIA-1/TIAR decreased not only the expression, but also the stability of TPD52 mRNA; it also decreased the expression and stability of the reporter gene ligated to the 3' end of the 78-280 fragment. Stimulation of TGF-b and EGF decreased the binding ability of these factors, resulted in decreased mRNA stability. These results indicate that the 78-280 fragment and TIA-1/TIAR concordantly contribute to mRNA stability as a cis -acting element and trans -acting factor(s), respectively. Thus, we herein report the specific interactions between these elements in the post-transcriptional regulation of the TPD52 gene.
- RNA-binding proteins
- post-transcriptional regulation
- mRNA stability
- ©2017 The Author(s)
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