Truncated HP1 lacking a functional chromodomain induces heterochromatinization upon in vivo targeting

Brink, Maartje C.; Velden, Yme van der; Leeuw, Wim de; Mateos‐Langerak, Julio; Belmont, Andrew S.; Driel, Roel van; Verschure, Pernette J.

doi:10.1007/s00418-005-0088-7

Cited by 16 publications

(10 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, we showed that in vivo targeting of HP1␣ or HP1␤ to an amplified chromosomal region causes local chromatin condensation, enhanced trimethylated H3K9me, and recruitment of histone methyltransferases (Verschure et al, 2005). Targeting of the HP1 lacking a functional CD also caused heterochromatinization of the amplified chromosome region (Brink et al, 2006). These results show that normal binding of HP1 through its CD domain, as well as artificial binding of HP1 without a CD through lac operator-lac Repressor interaction, is sufficient to trigger heterochromatin formation.…”

Section: Discussionmentioning

confidence: 83%

Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

Mateos‐Langerak

Brink

Luijsterburg

et al. 2007

MBoC

Self Cite

View full text Add to dashboard Cite

The heterochromatin protein 1 (HP1) family is thought to be an important structural component of heterochromatin. HP1 proteins bind via their chromodomain to nucleosomes methylated at lysine 9 of histone H3 (H3K9me). To investigate the role of HP1 in maintaining heterochromatin structure, we used a dominant negative approach by expressing truncated HP1␣ or HP1␤ proteins lacking a functional chromodomain. Expression of these truncated HP1 proteins individually or in combination resulted in a strong reduction of the accumulation of HP1␣, HP1␤, and HP1␥ in pericentromeric heterochromatin domains in mouse 3T3 fibroblasts. The expression levels of HP1 did not change. The apparent displacement of HP1␣, HP1␤, and HP1␥ from pericentromeric heterochromatin did not result in visible changes in the structure of pericentromeric heterochromatin domains, as visualized by DAPI staining and immunofluorescent labeling of H3K9me. Our results show that the accumulation of HP1␣, HP1␤, and HP1␥ at pericentromeric heterochromatin domains is not required to maintain DAPI-stained pericentromeric heterochromatin domains and the methylated state of histone H3 at lysine 9 in such heterochromatin domains. INTRODUCTIONThe HP1 (heterochromatin protein 1) gene was first discovered in Drosophila melanogaster as a mutant suppressing position effect variegation, a phenomenon in which a gene adjacent to a heterochromatin domain shows a mosaic expression pattern (James and Elgin, 1986;Eissenberg et al., 1990;Festenstein et al., 1999). Since then, a variety of HP1 homologues has been found in many eukaryotes (Li et al., 2002). There are at least three HP1 proteins in mammals. HP1␣ and HP1␤ are present in heterochromatic regions, whereas HP1␥ has been found either exclusively in euchromatin or in both euchromatin and heterochromatin (Wreggett et al., 1994;Horsley et al., 1996;Minc et al., 1999Minc et al., , 2000Cheutin et al., 2003). HP1 proteins are thought to have a role in gene regulation in a broad range of eukaryotes: from fission yeast to mammals (Hiragami and Festenstein, 2005;Hediger and Gasser, 2006).The HP1 gene products are proteins of ϳ180 amino acids, containing two protein-binding domains linked by a flexible hinge region. The chromodomain (CD) located at the Nterminal side of the hinge region specifically binds histone H3 methylated at lysine 9 (H3K9me; Bannister et al., 2001;Lachner et al., 2001;Jacobs and Khorasanizadeh, 2002), which is a marker for heterochromatin and is related to gene silencing (Cowell et al., 2002;Sims et al., 2003). HP1 is able to repress gene activity when artificially targeted to a site near a reporter gene (van der Vlag et al., 2000). The C-terminal part of HP1 contains the chromoshadow domain (CSD), which is partially homologous to the CD (Aasland and Stewart, 1995;Sims et al., 2003). The CSD binds to a consensus peptide that is present in a number of proteins, including the CSD of HP1 itself, thereby targeting proteins to heterochromatin and forming HP1 dimers (Brasher et al., 2000;Smothers and Henikoff, 2...

show abstract

Section: Discussionmentioning

confidence: 83%

Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

Mateos‐Langerak

Brink

Luijsterburg

et al. 2007

MBoC

Self Cite

View full text Add to dashboard Cite

show abstract

“…These results suggest that dSETDB1 is responsible for silencing the hsp26 promoter, and to a lesser extent, the hsp70 promoter. DISCUSSION Domain-dependent localization of HP1: The LacIlacO tethering system has proven useful for studies of chromosome pairing (Vazquez et al 2002), chromatin compaction (Verschure et al 2005;Brink et al 2006;Deng et al 2008;Strukov and Belmont 2009), and chromatin-mediated gene silencing (Danzer and Wallrath 2004). Previously, we demonstrated that LacI-HP1 rescues lethality in Su(var)2-5 mutants (Li et al 2003).…”

Section: Resultsmentioning

confidence: 99%

“…Hs-alpha , HP1 Hs-beta , or a CSD to reporter genes in mammalian cell culture studies caused H3K9me3, in this case by SETDB1 (Verschure et al 2005;Brink et al 2006). Likewise, targeting HP1…”

Section: Resultsmentioning

confidence: 99%

Domains of Heterochromatin Protein 1 Required forDrosophila melanogasterHeterochromatin Spreading

et al. 2009

View full text Add to dashboard Cite

Centric regions of eukaryotic genomes are packaged into heterochromatin, which possesses the ability to spread along the chromosome and silence gene expression. The process of spreading has been challenging to study at the molecular level due to repetitious sequences within centric regions. A heterochromatin protein 1 (HP1) tethering system was developed that generates ''ectopic heterochromatin'' at sites within euchromatic regions of the Drosophila melanogaster genome. Using this system, we show that HP1 dimerization and the PxVxL interaction platform formed by dimerization of the HP1 chromo shadow domain are necessary for spreading to a downstream reporter gene located 3.7 kb away. Surprisingly, either the HP1 chromo domain or the chromo shadow domain alone is sufficient for spreading and silencing at a downstream reporter gene located 1.9 kb away. Spreading is dependent on at least two H3K9 methyltransferases, with SU(VAR)3-9 playing a greater role at the 3.7-kb reporter and dSETDB1 predominately acting at the 1.9 kb reporter. These data support a model whereby HP1 takes part in multiple mechanisms of silencing and spreading.H ETEROCHROMATIN protein 1 (HP1) was identified in Drosophila as a nonhistone chromosomal protein enriched in centric heterochromatin ( James and Elgin 1986;James et al. 1989). On polytene chromosomes, HP1 localizes near centromeres and telomeres, along the fourth chromosome and at $200 sites within the euchromatic arms ( James et al. 1989;Fanti et al. 2003). Heterochromatin has the ability to ''spread,'' or propagate in cis, along the chromosome (Weiler and Wakimoto 1995). Spreading is observed when a chromosomal rearrangement places a euchromatic domain next to a heterochromatic domain. Cytologically, spreading is visualized as densely compact chromatin that emanates from the chromocenter, the structure formed by the fusion of centromeres, and extends into the banded regions of polytene chromosomes (Belyaeva and Zhimulev 1991). Euchromatic genes brought into juxtaposition with heterochromatin by chromosomal rearrangements exhibit gene silencing, termed position effect variegation (PEV) (Weiler and Wakimoto 1995). Mutations in Su(var)2-5, the gene encoding HP1, suppress silencing, suggesting HP1 plays a key role in spreading (Eissenberg et al. 1990). The molecular processes of spreading are not well understood.Repetitive sequences within heterochromatin make it difficult to study spreading at the molecular level. In addition, specific repetitive elements are thought to function as initiation sites for heterochromatin formation (Sun et al. 2004;Haynes et al. 2006), making it challenging to separate initiation from spreading. To overcome these problems, we generated a system that nucleates small domains (,20 kb) of repressive chromatin that share many properties with centric heterochromatin. Here we refer to these as ectopic heterochromatin domains. These domains are generated by expressing a fusion protein, consisting of the DNA binding domain of the Escherichia coli lac represso...

show abstract

“…11 Indeed, artificial targeting of HP1 to euchromatic sites is sufficient to induce gene repression and local condensation of chromatin in several experimental systems. [34][35][36][37] On a molecular level, HP1 might induce heterochromatin formation via cross-linking of nucleosomes in combination with the recruitment of other chromatin-modifying proteins. 38,39 The few instances where artificial HP1 targeting did not induce silencing 40 or the startling situations where HP1 has been implicated in gene activation 16,41,42 might be due to unique behavior of HP1 isoforms, distinct local chromatin environments, and the differential and regulated interaction with additional factors.…”

Section: Chromatin Histone Modifications Effector Proteins and Hetementioning

confidence: 99%

Dynamic Regulation of Effector Protein Binding to Histone Modifications: The Biology of HP1 Switching

Dormann¹,

Tseng²,

Allis³

et al. 2006

Cell Cycle

View full text Add to dashboard Cite

Truncated HP1 lacking a functional chromodomain induces heterochromatinization upon in vivo targeting

Cited by 16 publications

References 34 publications

Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

Domains of Heterochromatin Protein 1 Required forDrosophila melanogasterHeterochromatin Spreading

Dynamic Regulation of Effector Protein Binding to Histone Modifications: The Biology of HP1 Switching

Contact Info

Product

Resources

About