Expression regulation of a mature intronic miR3029 by 5′ UTR-like

Abstract

5′ UTR of the coding gene affected gene expression at the transcription and translation levels. For miRNA, 5′ UTR (termed 5′ UTR-like) is similar to UTR of encoding protein gene. However, the function of 5′ UTR-like has not been reported in the regulation of pre-miRNA formation and the process of miRNA’s formation. In this study, the regulated elements of 5′ UTR-like of intron miR3029 were analyzed by bioinformatics. The function analysis of primary structure of 5′ UTR-like was studied by the transient expression system of Arabidopsis thaliana protoplast. The function of second-structure stem loops of 5′ UTR-like was conducted by detecting the expression of miRNA3029 and pri-miRNA3029 in transgenic tobacco. In this study, we found that 5′ UTR-like region of miR3029 existences low temperature (LTR), oxygen stress element (ARE) and stem loop structure. These elements and structure may control miRNA’s stability and thereby affect the formation of mature miR3029. There also existed a translation enhancer similar to that of the UTRs of coding genes. The function analysis of second structure found that the predicted stem loop 5 can promote the expression of mature miR3029; stem loops 1, 2, 3 and 4 can inhibit the formation of mature miR3029. To sum up, this study lays a foundation for exploring the mechanism of how the primary transcript is cleaved into pre-miRNA, and provides reference for the study of the regulation of miRNA.