How and where to assemble heterochromatin, and why it is essential for organismal survival

Prof. Dr. Susan Gasser (Freidrich Miescher Institute for Biomedical Research)

27-Aug-2020, 08:00-10:00 (4 years ago)

Abstract: The establishment and maintenance of chromatin domains shape the epigenetic memory of a cell, with histone H3 lysine 9 methylation (H3K(me) defining repressed heterochromatin. In C. elegans, SET-25 (SUV39/g9a) catalyzes to its targets. One requires recognition of MET-2-mediated H3K9me2 by the MBT-domain protein LIN-61. The second depends on a somatic Argonaut NRDE-3 and 22nt siRNAs. This MET-2-independent pathway makes up ~10% of SET-25 target sequences, and most notably includes intact transposons. Compared to single mutants, met-2;nrde-3 double mutant enhances transposon transcription and embryonic lethality. Whereas the targeting of SET-25 silences transposons, whose expression compromises development, the targeting of MET-2/SET-DB1 is necessary to prevent the promiscuous transcription of simple repeats. Simple repeat transcripts lead to R-loops and fork-associated damage, that requires BRCA1 to ensure survival. While the genome becomes unstable, met-2 mutants show nearly normal developmental and differentiation patterns.

Biology

Audience: researchers in the discipline

( video )


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.

Organizers: Prof. Dr. Muhammad Tariq, Salman Tuasene Khawaja*, Hooraina Hassan Siddiqui*, Abdullah Jauhar*
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