A small RNA-based innate immune system guards the integrity of germ cell genomes

Abstract: PIWI-family proteins and their associated small RNAs (piRNAs) act in an evolutionarily conserved innate immune mechanism that provides an essential protection for germ cell genomes against the activity of mobile genetic elements. piRNA populations comprise a molecular definition of transposons that permits them to be distinguished from host genes and selectively silenced. piRNAs can be generated in two distinct ways. Primary piRNAs emanate from discrete genomic loci, termed piRNA clusters, and appear to be derived from long, single-stranded precursors. The biogenesis of primary piRNAs involves at least two nucleolytic steps. Zucchini cleaves piRNA cluster transcripts to generate monophosphorylated piRNA 5’ ends. piRNA 3’ ends are likely formed by exonucleolytic trimming, after a piRNA precursor is loaded into its PIWI partner. Secondary piRNAs arise during the adaptive ping-pong cycle, with their 5’ termini being formed by the activity of PIWIs themselves. At least in Drosophila, piRNAs are maternally deposited and transmit an epigenetic signal essential for the effective control of at least some transposable elements. Our continuing efforts combine genetics, biochemistry, structural biology, and evolutionary and computational approaches to understand how the piRNA pathway effectively discriminates self from non-self at the genomic level.

biochemistrycancer biologychemical biologycell biologydevelopmental biologydrug discoveryevolutiongeneticsimmunologymolecular biologymicrobiologyneuroscienceplant sciencessystems biologybiotechnologybiological techniquesbiophysics

Audience: researchers in the discipline

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Colloquium zooming Molecular & Cellular Biology LUMS

Series comments: Zooming Molecular & Cellular Biology Colloquium was initiated on July 28th, 2020 by the Biology department at Syed Babar Ali School of Science & Engineering (SBASSE), Lahore University of Management Sciences (LUMS). The series follows through various topics which come under the ambit of Molecular and Cellular Biology and we’ve had the pleasure and honor of hosting some of the most knowledgeable scientists from around the globe. Organizers can be reached out at 24100162@lums.edu.pk or 24100001@lums.edu.pk for the Zoom link of individual talks. All lectures are LIVE streamed on SBASSE's official Facebook page.