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Kang, H., McElroy, K.A., Jung, Y.L., Alekseyenko, A.A., Zee, B.M., Park, P.J., Kuroda, M.I. (2015). Sex comb on midleg (Scm) is a functional link between PcG-repressive complexes in Drosophila.  Genes Dev. 29(11): 1136--1150.
FlyBase ID
FBrf0228678
Publication Type
Research paper
Abstract

The Polycomb group (PcG) proteins are key regulators of development in Drosophila and are strongly implicated in human health and disease. How PcG complexes form repressive chromatin domains remains unclear. Using cross-linked affinity purifications of BioTAP-Polycomb (Pc) or BioTAP-Enhancer of zeste E(z), we captured all PcG-repressive complex 1 (PRC1) or PRC2 core components and Sex comb on midleg (Scm) as the only protein strongly enriched with both complexes. Although previously not linked to PRC2, we confirmed direct binding of Scm and PRC2 using recombinant protein expression and colocalization of Scm with PRC1, PRC2, and H3K27me3 in embryos and cultured cells using ChIP-seq (chromatin immunoprecipitation ChIP combined with deep sequencing). Furthermore, we found that RNAi knockdown of Scm and overexpression of the dominant-negative Scm-SAM (sterile α motif) domain both affected the binding pattern of E(z) on polytene chromosomes. Aberrant localization of the Scm-SAM domain in long contiguous regions on polytene chromosomes revealed its independent ability to spread on chromatin, consistent with its previously described ability to oligomerize in vitro. Pull-downs of BioTAP-Scm captured PRC1 and PRC2 and additional repressive complexes, including PhoRC, LINT, and CtBP. We propose that Scm is a key mediator connecting PRC1, PRC2, and transcriptional silencing. Combined with previous structural and genetic analyses, our results strongly suggest that Scm coordinates PcG complexes and polymerizes to produce broad domains of PcG silencing.

PubMed ID
PubMed Central ID
PMC4470282 (PMC) (EuropePMC)
Related Publication(s)
Research paper

Correspondence of Drosophila polycomb group proteins with broad H3K27me3 silent domains.
Jung et al., 2015, Fly 9(4): 178--182 [FBrf0232101]

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Secondary IDs
    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    Genes Dev.
    Title
    Genes & Development
    Publication Year
    1987-
    ISBN/ISSN
    0890-9369
    Data From Reference