About Alexei Aravin's Work
In animals, specific class of small RNA, piRNA, provide a defense system against the expression of genomic parasites, transposable elements. We found that piRNAs can induce transcriptional repression of their targets by establishing a repressive chromatin state. Our investigation of small RNA partners of bacterial Argonaute protein demonstrated that RNAi-related processes are ancient in origin and conserved across all three domains of life. Furthermore, they suggest that genome defense is the ancient function of RNAi.