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    Brown Lab

    Research Focus Teams: Alzheimer's, Arthritis, Autism, Cancer, COVID, Fertility, Rare Diseases

    location_on Floor 5

    Lab Team

    Carolyn Brown

    Professor

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    CONTACT

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    Samples in the lab being handled.
    Ali Salehi

    Rotation Student

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    Bronwyn Posynick

    Graduate Student

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    Christine Yang

    Lab Technician, Brown Lab

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    Karanveer Bhangu

    Graduate Student

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    Maria Jose Navarro Cobos

    Postdoctoral Fellow, Brown Lab

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    Rachel Jiang

    Graduate Student

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    Samantha Peeters

    Postdoctoral Fellow, Brown Lab

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    Sarah Baldry
    Sarah Baldry

    Lab Technician, Brown Lab

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    Ongoing Projects

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    Research Overview

    X-chromosome inactivation occurs early during mammalian development to transcriptionally silence one of the pair of X chromosomes in females, thereby achieving dosage equivalence with males who have a single X chromosome and the sex-determining Y chromosome. X chromosome inactivation is a truly remarkable example of both epigenetic determination (one of a pair of essentially identical chromosomes is chosen to be silenced) and of cell memory (the choice of chromosome inactivated is stably inherited throughout subsequent somatic divisions). Our research is directed to understanding the initiation of silencing through studies of XIST as well as how silencing is spread and maintained (or not in the case of genes escaping X inactivation).

    XIST

    The XIST gene is the only gene that is expressed from the inactive but not from the active X chromosome. This unique gene encodes a 17 kb alternatively spliced, processed transcript which is not translated into a protein but which remains in the nucleus where it associates with the inactive X chromosome. XIST was one of the first long non-coding RNAs (lncRNAs) to be discovered. Lab research projects are focussed on understanding how XIST localizes (C. Yang); how XIST establishes silencing and heterochromatin (M.J. Navarro Cobos) and the role of XIST in maintenance of X-chromosome inactivation (K. Bhangu).

    Escapees

    Surprisingly, over 15% of X-linked genes continue to be expressed from the otherwise inactive X chromosome. In collaboration with the Wasserman lab at BCCHRI we seek to identify the elements that allow genes to escape from silencing (S. Peeters, S. Baldry). Related to these studies we examine whether inactivation will spread into active genes inserted onto the inactive X chromosome (B. Posynick) and identify the boundaries separating active and silenced genes on the inactive X chromosome (B. Posynick, R. Jiang).