Modulation of Heterochromatin Protein 1 Dynamics in Primary Mammalian Cells

Science ◽  
2003 ◽  
Vol 299 (5607) ◽  
pp. 719-721 ◽  
Author(s):  
R. Festenstein
Keyword(s):  
Mammalian Cells ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein

scholarly journals KAP1 is an antiparallel dimer with a functional asymmetry

2019 ◽  
Vol 2 (4) ◽  
pp. e201900349 ◽  
Author(s):  
Giulia Fonti ◽  
Maria J Marcaida ◽  
Louise C Bryan ◽  
Sylvain Träger ◽  
Alexandra S Kalantzi ◽  
...  
Keyword(s):  
Single Molecule ◽  
Binding Sites ◽  
Mammalian Cells ◽  
Scattering Data ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Krab Domain ◽  
Functional Implications ◽  
New Gene ◽  
Expression In Mammalian Cells

KAP1 (KRAB domain–associated protein 1) plays a fundamental role in regulating gene expression in mammalian cells by recruiting different transcription factors and altering the chromatin state. In doing so, KAP1 acts both as a platform for macromolecular interactions and as an E3 small ubiquitin modifier ligase. This work sheds light on the overall organization of the full-length protein combining solution scattering data, integrative modeling, and single-molecule experiments. We show that KAP1 is an elongated antiparallel dimer with an asymmetry at the C-terminal domains. This conformation is consistent with the finding that the Really Interesting New Gene (RING) domain contributes to KAP1 auto-SUMOylation. Importantly, this intrinsic asymmetry has key functional implications for the KAP1 network of interactions, as the heterochromatin protein 1 (HP1) occupies only one of the two putative HP1 binding sites on the KAP1 dimer, resulting in an unexpected stoichiometry, even in the context of chromatin fibers.

scholarly journals The Assembly and Maintenance of Heterochromatin Initiated by Transgene Repeats Are Independent of the RNA Interference Pathway in Mammalian Cells

2006 ◽  
Vol 26 (11) ◽  
pp. 4028-4040 ◽  
Author(s):  
Fangwei Wang ◽  
Naoki Koyama ◽  
Hiroko Nishida ◽  
Tokuko Haraguchi ◽  
Walter Reith ◽  
...  
Keyword(s):  
Rna Interference ◽  
Mammalian Cells ◽  
Cytosine Methylation ◽  
Chromatin Condensation ◽  
Rnai Pathway ◽  
Small Interfering Rnas ◽  
Heterochromatin Protein 1 ◽  
Independent Manner ◽  
Heterochromatin Protein ◽  
Cpg Dinucleotides

ABSTRACT A role for the RNA interference (RNAi) pathway in the establishment of heterochromatin is now well accepted for various organisms. Less is known about its relevance and precise role in mammalian cells. We previously showed that tandem insertion of a 1,000-copy inducible transgene into the genome of baby hamster kidney (BHK) cells initiated the formation of an extremely condensed chromatin locus. Here, we characterized the inactive transgenic locus as heterochromatin, since it was associated with heterochromatin protein 1 (HP1), histone H3 trimethylated at lysine 9, and cytosine methylation in CpG dinucleotides. Northern blot analysis did not detect any transgene-derived small RNAs. RNAi-mediated Dicer knockdown did not disrupt the heterochromatic transgenic locus or up-regulate transgene expression. Moreover, neither Dicer knockdown nor overexpression of transgene-directed small interfering RNAs altered the bidirectional transition of the transgenic locus between the heterochromatic and euchromatic states. Interestingly, tethering of HP1 to the transgenic locus effectively induced transgene silencing and chromatin condensation in a Dicer-independent manner, suggesting a role for HP1 in maintaining the heterochromatic locus. Our results suggest that the RNAi pathway is not required for the assembly and maintenance of noncentromeric heterochromatin initiated by tandem transgene repeats in mammalian cells.

scholarly journals KAP1 is an antiparallel dimer with a natively functional asymmetry

2019 ◽  
Author(s):  
Giulia Fonti ◽  
Maria J. Marcaida ◽  
Louise C. Bryan ◽  
Sylvain Traeger ◽  
Alexandra S. Kalantzi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Molecule ◽  
Binding Sites ◽  
Mammalian Cells ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Krab Domain ◽  
Sumo Ligase ◽  
Functional Implications ◽  
Expression In Mammalian Cells

AbstractKAP1 (KRAB-domain associated protein 1) plays a fundamental role in regulating gene expression in mammalian cells by recruiting different transcription factors and altering the chromatin state. In doing so, KAP1 acts both as a platform for macromolecular interactions and as an E3 SUMO ligase. This work sheds light on the overall organization of the full-length protein combining solution scattering diffraction data, integrative modeling and single-molecule experiments. We show that KAP1 is an elongated antiparallel dimer with a native asymmetry at the C-terminal domain. This conformation supports our finding that the RING domain contributes to KAP1 auto-SUMOylation. Importantly, this intrinsic asymmetry has key functional implications for the KAP1 network of interactions, as the heterochromatin protein 1 (HP1) occupies only one of the two putative HP1 binding sites on the KAP1 dimer, resulting in an unexpected stoichiometry, even in the context of chromatin fibers.

scholarly journals BRD4 facilitates DNA damage response and represses CBX5/Heterochromatin protein 1 (HP1)

Oncotarget ◽  
2017 ◽  
Vol 8 (31) ◽  
pp. 51402-51415 ◽  
Author(s):  
Georgios Pongas ◽  
Marianne K. Kim ◽  
Dong J. Min ◽  
Carrie D. House ◽  
Elizabeth Jordan ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Damage Response
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