Does cohesin regulate developmental gene expression in Drosophila?
نویسنده
چکیده
C ohesin is a conserved protein complex with a well documented role in providing stable but reversible connections between sister chromatids during both mitosis and meiosis. Cohesin consists of two long coiled-coil proteins (SMC1 and SMC3) and two non-SMC subunits (SCC1/Rad21 and SCC3/SA) that combine to form a ring-like structure. Establishment, maintenance, and timely removal of cohesin-mediated cohesion is critical to ensure regular chromosome segregation (1–3). However, recent findings indicate that in higher eukaryotes chromosome segregation may not be the only major function of cohesin. Several studies have shown an effect of reduction in dose or expression of genes encoding cohesin subunits and of the cohesin loading factor Nipped-B/SCC2 on expression of the cut locus in Drosophila (4–6). Two articles published earlier this year demonstrated that cohesin mutations in Drosophila disrupt axon pruning at a postmitotic stage in development of the Drosophila nervous system by inhibiting expression of the Ecdysone-Receptor (EcR) gene (7, 8). In this issue of PNAS, Hallson et al. (9) suggest a considerably broader role of cohesin in gene regulation in Drosophila. Their findings indicate that mutations in the gene encoding the Rad21 cohesin subunit interact with mutations in hedgehog (hh), a signal-transduction gene with multiple developmental roles (10), and in Polycomb (Pc), which encodes a component of a chromatin complex responsible for silencing expression of multiple homeotic genes during development. These phenotypes are characteristic of mutations in trithorax-group (trxG) genes, which encode a diverse group of chromatin proteins required to counteract Polycomb group (PcG)-mediated silencing and maintain appropriate expression of several genes important for proper identity of Drosophila segments and other developmental processes (11– 13). Thus, the findings of Hallson et al. (9) suggest that cohesin may play a fundamental role in developmental gene regulation in addition to its established role in chromosome segregation.
منابع مشابه
Gene Regulation: The Cohesin Ring Connects Developmental Highways
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The cohesin protein complex is a conserved structural component of chromosomes. Cohesin binds numerous sites along interphase chromosomes and is essential for sister chromatid cohesion and DNA repair. Here, we test the idea that cohesin also regulates gene expression. This idea arose from the finding that the Drosophila Nipped-B protein, a functional homolog of the yeast Scc2 factor that loads ...
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The cohesin protein complex was first recognized for holding sister chromatids together and ensuring proper chromosome segregation. Cohesin also regulates gene expression, but the mechanisms are unknown. Cohesin associates preferentially with active genes, and is generally absent from regions in which histone H3 is methylated by the Enhancer of zeste [E(z)] Polycomb group silencing protein. Her...
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BACKGROUND Developmental abnormalities observed in Cornelia de Lange syndrome have been genetically linked to mutations in the cohesin machinery. These and other recent experimental findings have led to the suggestion that cohesin, in addition to its canonical function of mediating sister chromatid cohesion, might also be involved in regulating gene expression. RESULTS We report that cleavage...
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عنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 105 34 شماره
صفحات -
تاریخ انتشار 2008