Research topic of training

The topic of the early stage research training will be on the function of small non-coding RNAs, in particular on micro RNAs (acronym miRNA). MiRNAs are small endogenous RNAs of about 22 nucleotides in size that are found in animals and plants. They were discovered in Nov 2001 as a new and so far overlooked class of non-coding RNAs that play important regulatory roles in gene expression. Small RNAs were classified as the scientific breakthrough of the year 2002 by Science magazine. The small miRNAs interfere with mRNA function by base-pairing. The sequence complementarity is specific, but in most cases not perfect. The RNA-RNA interaction results in either translational repression or cleavage of the mRNA target via the RNAi pathway. In either case, the miRNA is a negative modulator of gene expression. MiRNAs are encoded from endogenous genes in the form of precursor transcripts that are then processed by the ribonucleases nucleases Drosha and Dicer into the mature miRNA. Many miRNAs are conserved in sequence in closely related organisms. Several hundreds of miRNAs have been discovered so far. The expression of miRNA genes is tissue-specific and developmentally regulated, so that each cell might have its own and specific miRNA expression profile. Only relatively few validated mRNA targets are currently known. However, a given miRNA may bind to several mRNA targets and any mRNA may interact with more than one type of miRNA. This results in a complex regulatory network. The picture emerging suggests that miRNA play a fundamental role in regulating several developmental processes in plants and animals, ranging from leaf morphology to neuronal processes. Four research teams of our Institute have joined forces. We plan to take advantage of the recent surge of data on miRNAs along with the common interest on this topic to offer an EST mono-site to train visiting graduate students in this newly emerging field. The research conducted within the frame of the proposed EST activity will very likely contribute to identifying and characterising the functional role of miRNAs during early developmental processes in various organisms.