Molecular mechanisms of mammalian germline small RNAs that ensure genome integrity

• Applicant: Dr. Michael Reuter
• Subject Area: General Genetics and Functional Genome Biology
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 162697145

A large part (~50%) of eukaryotic genomes is constituted by transposons. They propagate themselves in the population by insertion into new genomic locations. This could result in insertion mutations of protein-coding genes. In dividing cells transposon activity could cause chromosome breakage and genome rearrangements. To specifically identify transposons in the germline and combat their potentially harmful effects the host genome has evolved ~24-30 nucleotides small RNAs (piRNAs), which associate with RNA-binding proteins called piwi proteins. How these piwi proteins in concert with their associated piRNAs mechanistically mediate the recognition and silencing of transposons in the germline is the main interest of our research. To analyze the piRNA pathway, piwi protein-associated factors were identified and characterized. As one result of these investigations, we recently described the functional role of a tudor domain containing protein (Tdrd1) in a piwi protein-complex. In this proposal I extend these studies by the identification of Tdrd1-associated proteins to gain further information of the specific role of Tdrd1 in the piRNA pathway. It will also describe studies on another piwi complex, where I initiated the creation of a novel knock-in mouse mutant. The mutation is supposed to interrupt the enzymatic activity of the piwi protein, which promises to address questions that are fundamental to the understanding of piRNA biogenesis. This study will employ bioinformatics, biochemistry and mouse genetics tools already available in the host institution to achieve its aims. In general, experiments suggested in this proposal are bound to shed light on the biogenesis and silencing role of small RNAs required for mammalian genome integrity.

• DFG Programme: Research Fellowships
• Host: Professor Ramesh S. Pillai, Ph.D.