Research progress of miRNA and siRNA in spinocerebellar ataxia type 3

Abstract

Spinocerebellar ataxia type 3 (SCA3) is a type of polyglutamine (polyQ) disease with expansion mutant ATXN3 gene as its causative gene which contains cytosine-adenine-guanine (CAG) repeat sequence at the coding region of 3-terminal. The polyQ expansion mutant ATXN3 gene encoded polyQ expansion mutant ataxin-3 protein with a polyQ peptide chain at its carboxyl-terminal. The polyQ expansion mutant ataxin-3 protein selectively accumulates in specific areas of the central nervous system, such as cerebellum, brainstem, spinal cord, etc, and forms neuronal intranuclear inclusions (NⅡs). Researches about micro RNA (miRNA) and small interference RNA (siRNA) are dramatically rapidly increasing. miRNAs are a class of small non-coding RNAs that widely exist in higher eukaryotes, with approximately 21-23 bp. They inhibit target gene expression by combining with the 3' untranslated region (3'UTR) of the target gene mRNA. siRNAs are the effect molecules in RNA interference (RNAi) technology, with a length of about 21-23 bp. They induce mRNA degradation and silence on the basis of completely complementary combination with mRNA coding sequence (CDS). miRNA and siRNA have many similarities in both structure and mechanism, and both of them can be used to analyze gene function and to investigate pathogenesis of diseases.