THE CHARACTERISTICS OF MIRNA BINDING SITES IN MRNA OF ZFHX3 GENE AND ITS ORTHOLOGS

Abstract

Transcription factor gene ZFHX3 is one of the candidate genes involved in stroke development. The ZFHX3 protein contains oligopeptides encoded by trinucleotide repeats (TNRs). TNR variability is considered to be one of the causes of the disease, but their biological function has not yet been established. We assume that TNRs are the binding sites of miRNA to mRNA and are involved in regulation of ZFHX3 gene expression. The characteristics of miRNA–mRNA interaction were determined using MirTarget software. It has been shown that the first TNR in mRNA of the human ZFHX3 gene consists of the seven consecutive miR-12-32603-3p binding encoding polyGlu. The ZFHX3 protein of human polyGlu contains 30 Glu. In the orthologous proteins of 36 animal species the length of polyGlu varied from 27 Glu to 33 Glu. Negatively charged polyGlu of the ZFHX3 transcription factor probably interacted with positive DNA-binding proteins. The following mRNA region of the ZFHX3 gene contained the binding sites for miR-17-39416-3p, miR-5-15733-3p, miR-9-20317-3 encoding polyAla by 15 Ala lengths. In the 33 ZFHX3 orthologous proteins polyAla had the same length. The mRNA region of the human ZFHX3 gene with binding polysite of miR-1322-3p encoded polyGln consisting of 19 Gln. In the 41 orthologs of the ZFHX3 protein the length of polyGln varied from seven Gln to 23 Gln. The binding sites of miR-2-6184-3p, miR-5-14114-5p and miR-19-43437-5p were located with overlapping nucleotides sequences, and encode polyPro. In ZFHX3 human polyPro consisted of 12 Pro. In the orthologs, polyPro contained from 10 Pro to 14 Pro. The binding sites of miR-17-39416-3p, miR-9-20317-3p, miR-1-1819-3p, miR-5-15733-3p, miR-6-17815-3p, miR-18-39953-5p, miR-26862-5p, miR-1260b and miR-X-48174-3p in human ZFHX3 encoded polyGly by 22 Gly length. In the 28 orthologs of ZFHX3 the length of polyGly decreased to 11 Gly. The TNR regions could simultaneously bind several miRNAs, which increased the dependence of gene expression on miRNA. The oligopeptides encoded by the binding polysites of miRNA in mRNA in the orthologous ZFHX3 proteins were flanked by conserved oligopeptides.