Isoforms of elongation factor eEF1A may be differently regulated at post-transcriptional level in breast cancer progression

A A Vislovukh,R S Groisman,B S Negrutskii,M G Naumovets,I S Groisman,M I Kovalenko,A V El'Skaya

doi:10.7124/bc.000806

A A Vislovukh, R S Groisman + Show 5 more

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https://doi.org/10.7124/bc.000806

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Abstract

Eukaryotic translation elongation factor 1A exists as two 98 % homologous isoforms: eEF1A1 (A1) and eEF1A2 (A2) which are tissue and development specific. Despite high homology in an open reading frame (ORF) region, mRNAs coding for eEF1A1 and eEF1A2 are different in their untranslated regions (UTR), suggesting a possibility of their dissimilar post-transcriptional regulation. Aim. To analyze the existence of cis-acting motifs in the UTRs of EEF1A1/A2 mRNAs, to confirm the possibility of post-transcriptional control of eEF1A1 and eEF1A2 expression. Methods. An ensemble of bioinformatic methods was applied to predict regulatory motifs in the UTRs of EEF1A1/A2 mRNAs. Dual-luciferase reporter assay was employed to detect post-transcriptional regulation of eEF1A1/A2 expression. Results. Numerous regulatory motifs in the UTR of EEF1A1/A2 mRNAs were found bioinformatically. The experimental evidence was obtained for the existence of negative regulation of EEF1A1 and positive regulation of EEF1A2 mRNA in the model of breast cancer development. Conclusions. EEF1A1 and EEF1A2 mRNAs contain distinct motifs in the UTRs and are differently regulated in cancer suggesting the possibility of their control by different cellular signals.

Highlights

The main function of eukaryotic translation elongation factor 1A is delivery of aminoacylated tRNA to the A-site of ribosome during the elongation step of protein biosynthesis [1]. eEF1A exists as two isoforms that are tissue and development specific
The 3'untranslated regions (UTR) of EEF1A2 mRNA was amplified from genomic DNA extracted from human leukocytes using following primers: forward – 5'-GCTCTAGAGCCCG CGGCGCGACCCTCCC-3'; reverse – 5'-GCTCTAG AGAGCGTGGCGAGCGCTGGGC-3
We found that in mRNAs coding for the eEF1A1 and eEF1A2 isoforms AUG start codons are in strong Kozak context (Fig. 1, A, B)

Summary

Introduction

The main function of eukaryotic translation elongation factor 1A (eEF1A) is delivery of aminoacylated tRNA to the A-site of ribosome during the elongation step of protein biosynthesis [1]. eEF1A exists as two isoforms that are tissue and development specific. In abovementioned tissues, during postnatal period a switch from eEF1A1 to eEF1A2 expression occurs. This change of their expression is crucial, as the mice with a partial deletion of the EEF1A2 gene die on the 28th day after birth [3]. Ó Institute of Molecular Biology and Genetics, NAS of Ukraine, 2013 catalytic efficacy during the elongation step of protein biosynthesis, the isoforms seem to be different in their non-canonical functions [4,5,6]. MRNAs coding for the A1 and A2 isoforms have different 5' and 3'UTRs. It is well known that through UTRs occurs the post-transcriptional regulation of gene expression [11].

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