[bioundgrd] FW: Microbiome Club Seminar Tuesday 5/14 @ 1PM in 56-614

[Joshua Stone]

From: Chelsea Catania <cataniac at mit.edu>
Subject: Microbiome Club Seminar Tuesday 5/14 @ 1PM in 56-614

MIT Microbiome Club
Postdoc Seminar
[cid:DE188664-4E8D-43E8-AA08-7505B7991C01 at broadinstitute.org]
Dr. Brantley Hall
Invertible promoters mediate microbial adaptation to the human gut
Tuesday, May 14th at 1:00PM in 56-614<https://whereis.mit.edu/?go=56>
Phase variation, the alternation between multiple states in a heritable but reversible manner, regulates genes that mediate key host-microbe interactions enabling infection by pathogens and colonization by commensals. Bacterial species can implement phase variation by inverting regions of their genome containing regulatory regions such as promoters or coding sequences (CDS). Despite their importance, few instances of phase variation have been characterized in species of the gut microbiome and the orientations of invertible DNA regions have rarely been characterized in vivo. We developed the PhaseFinder algorithm to systematically identify phase variation mediated by invertible DNA regions and quantify the orientations of invertible DNA regions using metagenomic data. A systematic search of 54,875 bacterial genomes identified 4,686 invertible DNA regions and revealed an enrichment in gut bacteria. Invertible DNA regions were found in 10 of 19 bacterial phyla. Most invertible DNA regions in gut bacteria contain invertible promoters which typically regulate extracellular products underscoring the importance of surface diversity for gut colonization. Nine examples of invertible CDS involving swapping specificity domains of methyltransferases to generate epigenetic diversity were identified in Actinobacteria species. We discovered that Akkermansia species have 25-29 invertible promoters all regulated by a global invertase that recognizes a conserved inverted repeat motif. Finally, we used fecal microbiota transplant (FMT) to observe the orientations of invertible promoters from the same strain in a donor before FMT and in patients afterwards to show that the orientation of invertible promoters are influenced by host-specific selective forces contributing to their interhost variability.

Bio: Brantley Hall is a Helen Hay Whitney Postdoctoral Fellow at the Broad Institute in the laboratory of Ramnik Xavier. He uses a combination of wet and dry lab techniques to study the genomics of gut microbes and understand the reasons for alterations to the gut microbiome in inflammatory bowel disease.
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The MIT Microbiome Club, part of the Center for Microbiome Informatics and Therapeutics, brings together inquisitive MIT undergrads, grad researchers, postdocs, faculty, and clinicians in the emerging field of microbiome studies and microbiome-based medicine. Learn more on our Facebook page. <https://www.facebook.com/MITmicrobiomeclub/> Or follow us on Twitter<https://twitter.com/MITubiomeclub>.

Chelsea Catania, Ph.D.
MIT Microbiome Club President
Postdoctoral Associate
Laboratory for Energy and Microsystems Innovation
Department of Mechanical Engineering
@MITubiomeclub<https://twitter.com/MITubiomeclub>

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