Post-transcriptional regulation of microRNA expression in Arabidopsis and crop plants
In this seminar, hosted by Craig Simpson and Csaba Hornyik from our Cell and Molecular Sciences group, Professor Zofia Szweykowska-Kulińska will discuss findings of strong competition between the essential splicing component U1snRNP the Arabidopsis microprocessor during intronic miR402 biogenesis, in the context of extensive posttranscriptional regulation in plant microRNAs.
Abstract
Plant microRNAs undergo extensive posttranscriptional regulation. Introns and active 5' splice sites stimulate the accumulation of microRNAs encoded within the first exon of intron-containing MIR genes. However, we found strong competition between the essential splicing component U1snRNP and the Arabidopsis microprocessor during intronic miR402 biogenesis. Details of miR402 biogenesis regulation will be discussed in the seminar. We further showed that SERRATE protein (the key component of the plant microprocessor) interacts with selected U1snRNP proteins showing a direct link between the splicing machinery and microprocessor.
Post-transcriptional regulation of microRNA biogenesis is also important in crop plants. Barley miR444 is induced under heat stress and proper splicing is required for its accumulation. Heat-induced miR444 accumulation is responsible for inhibition of tillering in barley. Our results show new ways to regulate plant MIR gene expression and consequently regulation of their target genes.
Biography
Professor Szweykowska-Kulińska studies mRNA and microRNA biogenesis. She studies the role of key RNA metabolism proteins involved in mRNA and miRNA biogenesis and maturation. In particular, cap binding proteins, CBP20, CBP80, and the pri-miRNA maturation protein SERRATE, which she and her colleagues have discovered have an important role in pre-mRNA splicing. She is investigating the formation of a protein complex (HYL1 (DRB1), SERRATE, CBP20, CBP80, DDL, DCL1) involved in micro RNA biogenesis and the role of other proteins (RNA dependent RNA polymerases and chromatin remodelling proteins) in this process. Her team use microscopic techniques, such as BiFC and FRET to investigate these protein-protein interactions and their role in micro RNA biogenesis.
One of the most important environmental conditions for Poland is water shortage and spring/summer drought threat. Her studies allowed identification of several proteins engaged in RNA metabolism that affect drought stress response and she has put a lot of effort into applying these findings to crop plants. For example, she has analysed the role of micro RNAs to drought in potato, and obtained plants with increased tolerance to water shortage. In these studies she used artificial micro RNAs and an RNAi approaches to silence the activity of selected potato genes.
