Ramesh Pillai

Host Institution : EMBL

Laboratory : EMBL-Grenoble Outstation

Call for projects : Starting (LS1)

Name of the project : PISILENCE – Small RNA-guided complex machinery for epigenetic silencing

Amount : 0.9 M€

Description : 

Transposons are parasitic DNA elements that when activated can insert into new genomic locations, leading to genome instability. Animal germlines express a special class of small RNAs called piwi-interacting RNAs (piRNAs) which are implicated in transposon silencing. In mammals, they are believed to promote DNA methylation of transposon-rich genomic regions. Mechanisms of piRNA biogenesis and function are only beginning to be understood. Sequence analysis of piRNAs from a variety of organisms has given rise to working models for piRNA biogenesis and how piRNAs might act as guides for nuclear silencing complexes. However, key components of the pathway, especially those for biogenesis and function, remain to be discovered. Our aim is to identify and characterize new components using a combination of biochemistry, mouse genetics and small RNA bioinformatics. The regulatory potential of posttranslational modification of piwi proteins and their recognition by tudor proteins will be examined. Mouse mutants will be used to study the in vivo role of catalytic activity of piwi proteins in piRNA biogenesis and identify putative targets by transcriptomics approaches. Integrated biochemical and deep-sequencing methods will be applied to understand how small RNAs might guide nulcear silencing machinery to target locations. Finally, in a field that is dependent on model organisms, we propose to develop a cell culture system to study the piRNA pathway and carry out a high-throughput functional RNAi screen for component discovery. This proposal aims to use interdisciplinary approaches in uncovering the biochemical framework in which germline small RNAs function to protect eukaryotic genomes.