Transcriptional repression mediated by polycomb group proteins and other chromatin-associated repressors is selectively blocked by insulators

被引:64
作者
van der Vlag, J [1 ]
den Blaauwen, JL [1 ]
Sewalt, RGAB [1 ]
van Driel, R [1 ]
Otte, AP [1 ]
机构
[1] Univ Amsterdam, BioCentrum Amsterdam, EC Slater Inst, NL-1018 TV Amsterdam, Netherlands
关键词
D O I
10.1074/jbc.275.1.697
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Polycomb group (PcG) proteins repress gene activity over a considerable distance, possibly by spreading along the chromatin fiber. Insulators or boundary elements, genetic elements within the chromatin, may serve to terminate the repressing action of PcG proteins. We studied the ability of insulators to block the action of chromatin-associated repressors such as PcG proteins, HP1, and MeCP2. We found that the Drosophila special chromatin structure insulator completely blocks transcriptional repression mediated by all of the repressors we tested. The Drosophila gypsy insulator was able to block the repression mediated by the PcG proteins Su(z)2 and RING1, as well as mHP1, but not the repression mediated by MeCP2 and the PcG protein HPC2. The 5'-located DNase I-hypersensitive site in the chicken beta-globin locus displayed a limited ability to block repression, and a matrix or scaffold attachment region element was entirely unable to block repression mediated by any repressor tested. Our results indicate that insulators can block repression mediated by PcG proteins and other chromatin-associated repressors, but with a high level of selectivity. This high degree of specificity may provide a useful assay to define and characterize distinct classes of insulators.
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页码:697 / 704
页数:8
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