Perinuclear localization of slow troponin C m RNA in muscle cells is controlled by a cis-element located at its 3′ untranslated region

Abstract

The process of mRNA localization within a specific cytoplasmic region is an integral aspect of the regulation of gene expression. Furthermore, colocalization of mRNAs and their respective translation products may facilitate the proper assembly of multisubunit complexes like the thick and thin filaments of muscle. This postulate was tested by investigating the cytoplasmic localization of three mRNAs-the ␣-actin, slow troponin C (sTnC), and slow troponin I (sTnI), which encode different polypeptide partners of the thin filament. Using in situ hybridization we showed that all three thin filament mRNAs are localized in the perinuclear cytoplasm of cultured C 2 C 12 muscle cells. Their localization differs from that of the nonmuscle ␤-actin mRNA, which is localized in the peripheral region of both proliferating nondifferentiated myoblasts and the differentiated myocytes. Analysis of the localization signal of the sTnC mRNA showed that a 40-nucleotide-long region of the sTnC mRNA 3 UTR is sufficient to confer the perinuclear localization on a heterologous reporter ␤-Gal mRNA. This localization signal showed tissue specificity and worked only in the differentiated myocytes, but not in the proliferating myoblasts or in HeLa cells. The predicted secondary structure of the localization signal suggests the presence of multiple stem and loop structures in this region of the 3 UTR. Mutations within the stem region of the localization signal, which abolish the base pairing in this region, significantly reduced its perinuclear mRNA localization activity. Using UV-induced photo-cross-linking of RNA and proteins we found that a myotube-specific 42-kDa polypeptide binds to the localization signal.

Polymorphism in 3′‐untranslated region of toll‐like receptor 4 gene is associated with protection from hepatitis B virus recurrence after liver transplantation

“…Recent studies reveal that the 3′‐UTR of mRNA can regulate the expression of genes by influencing the stability, the location, as well as translational efficiency of the mRNA (22–26). The TLR4/11367 polymorphism can alter post‐transcriptional regulation of the 3′‐UTR and expression of the target gene to attenuate the lipopolysaccharide‐induced transmembrane signaling (27).…”

Functional variant in the 3’-untranslated region of toll-like receptor 4 is associated with nasopharyngeal carcinoma risk

“…11,23 Recent findings show that the 3'-UTR of mRNA may control mRNA activity 24 and affect several processes, such as efficiency of mRNA formation, 25 mRNA stability, 26,27 post-transcriptional modification and degradation, 25,28 mRNA transport and localization 29 and translation. 30 In the present study, we tested the function of the SNP 11350G/C in the TLR4 3'-UTR on gene expression.…”

Hairpin RNA: a secondary structure of primary importance

“…2) is bound by a myotube-specific 42-kDa polypeptide, and perinuclear localization is observed in differentiated myocytes but not in proliferating myoblasts or HeLa cells. Mutations within the stem region of the localization signal reduce perinuclear mRNA localization [39]. The perinuclear localization of rat metallothionein-1 mRNA is also dependent on the 3¢ UTR.…”

“…This localization is dependent on the 3¢ UTR, and necessary sequences are found in predicted hairpin structures [36][37][38][39]. Putative perinuclear localization signals do not share apparent sequence or structural similarity (Fig.…”