Arabidopsis thaliana microRNA162 level is posttranscriptionally regulated via splicing and polyadenylation site selection.

Abstract

Arabidopsis microRNA162 level regulation was studied under abiotic stresses such as drought and salinity. The TaqMan® microRNA assay proved that A. thaliana miRNA162 level was elevated under these stresses confirming its salt and drought responsiveness. Consistently, the MIR162a and MIR162b gene promoter region analyses identified numerous salinity and drought responsive elements. However, our analyses show that generally MIR162b is rather weakly expressed, both in control and stress conditions. On the other site the stress-dependent regulation of the pri-miRNA162a alternative splicing pattern revealed the increase of functional pri-miR162a isoform and preferential distal polyA site selection in stress conditions. Apart from the potential transcriptional regulation of the miRNA genes (MIRs) expression the data obtained point to an essential role of posttranscriptional regulation of the microRNA162 level.