Approximately half of the sequence of human and mouse genomes are derived from mobile elements. Much of this DNA is no longer capable of mobilization but is likely “auditioning” for a role, for example, in homologous recombination or regulation of gene expression. Modern mammalian genomes also contain numerous intact copies of retrotransposon LINE-1 that utilizes RNA intermediate to spread about the genome.
Given the crucial role of germ cells in the propagation of species, their genomes are particularly attractive for mobile elements. Uncontrolled activity of retrotransposons is known to cause mutations or even kill germ cells necessitating existence of specialized defensive mechanisms regulating LINE-1 elements.
Our group focuses on:
1. Molecular mechanisms of restraining LINE-1 mobilization in mouse embryonic and adult germ cells.
We approach this problem through the analysis of function of Maelstrom, a conserved protein implicated in transposon silencing in flies and mice by means of specialized small RNAs known as Piwi-interacting RNAs (or piRNAs).
2. The impact of LINE-1 on development, differentiation and function of mouse germ cells.
We posit that the never-ending battle between the genome and selfish elements has profoundly influenced germ cell biology in the course of evolution. We are trying to understand how LINE-1 elements impact germ cells in the course of their normal development and differentiation, particularly during meiosis.