scholarly journals Heterochromatin protein 1 is recruited to various types of DNA damage

2009 ◽  
Vol 185 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Martijn S. Luijsterburg ◽  
Christoffel Dinant ◽  
Hannes Lans ◽  
Jan Stap ◽  
Elzbieta Wiernasz ◽  
...  
Keyword(s):  
Dna Damage ◽  
Uv Light ◽  
High Sensitivity ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Strand Breaks ◽  
Essential Components ◽  
Associated Proteins ◽  
Chromo Shadow Domain ◽  
Hp1 Proteins

Heterochromatin protein 1 (HP1) family members are chromatin-associated proteins involved in transcription, replication, and chromatin organization. We show that HP1 isoforms HP1-α, HP1-β, and HP1-γ are recruited to ultraviolet (UV)-induced DNA damage and double-strand breaks (DSBs) in human cells. This response to DNA damage requires the chromo shadow domain of HP1 and is independent of H3K9 trimethylation and proteins that detect UV damage and DSBs. Loss of HP1 results in high sensitivity to UV light and ionizing radiation in the nematode Caenorhabditis elegans, indicating that HP1 proteins are essential components of DNA damage response (DDR) systems. Analysis of single and double HP1 mutants in nematodes suggests that HP1 homologues have both unique and overlapping functions in the DDR. Our results show that HP1 proteins are important for DNA repair and may function to reorganize chromatin in response to damage.

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

scholarly journals Heterochromatin Protein 1 (HP1) Proteins Do Not Drive Pericentromeric Cohesin Enrichment in Human Cells

PLoS ONE ◽  
2009 ◽  
Vol 4 (4) ◽  
pp. e5118 ◽  
Author(s):  
Ángel Serrano ◽  
Miriam Rodríguez-Corsino ◽  
Ana Losada
Keyword(s):  
Human Cells ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Hp1 Proteins

scholarly journals The Dark Side of UV-Induced DNA Lesion Repair

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1450
Author(s):  
Wojciech Strzałka ◽  
Piotr Zgłobicki ◽  
Ewa Kowalska ◽  
Aneta Bażant ◽  
Dariusz Dziga ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Uv Light ◽  
Genetic Material ◽  
Dna Lesions ◽  
Dark Side ◽  
Repair System ◽  
Strand Breaks ◽  
Dna Lesion ◽  
Pyrimidine Dimers

In their life cycle, plants are exposed to various unfavorable environmental factors including ultraviolet (UV) radiation emitted by the Sun. UV-A and UV-B, which are partially absorbed by the ozone layer, reach the surface of the Earth causing harmful effects among the others on plant genetic material. The energy of UV light is sufficient to induce mutations in DNA. Some examples of DNA damage induced by UV are pyrimidine dimers, oxidized nucleotides as well as single and double-strand breaks. When exposed to light, plants can repair major UV-induced DNA lesions, i.e., pyrimidine dimers using photoreactivation. However, this highly efficient light-dependent DNA repair system is ineffective in dim light or at night. Moreover, it is helpless when it comes to the repair of DNA lesions other than pyrimidine dimers. In this review, we have focused on how plants cope with deleterious DNA damage that cannot be repaired by photoreactivation. The current understanding of light-independent mechanisms, classified as dark DNA repair, indispensable for the maintenance of plant genetic material integrity has been presented.

scholarly journals Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

2007 ◽  
Vol 18 (4) ◽  
pp. 1464-1471 ◽  
Author(s):  
Julio Mateos-Langerak ◽  
Maartje C. Brink ◽  
Martijn S. Luijsterburg ◽  
Ineke van der Kraan ◽  
Roel van Driel ◽  
...  
Keyword(s):  
Histone H3 ◽  
Dominant Negative ◽  
Pericentromeric Heterochromatin ◽  
Heterochromatin Protein 1 ◽  
Dapi Staining ◽  
Heterochromatin Protein ◽  
3T3 Fibroblasts ◽  
Heterochromatin Structure ◽  
Hp1 Proteins

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 HP1α or HP1β proteins lacking a functional chromodomain. Expression of these truncated HP1 proteins individually or in combination resulted in a strong reduction of the accumulation of HP1α, HP1β, and HP1γ in pericentromeric heterochromatin domains in mouse 3T3 fibroblasts. The expression levels of HP1 did not change. The apparent displacement of HP1α, HP1β, and HP1γ 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 HP1α, HP1β, and HP1γ 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.

scholarly journals Direct Interaction between DNA Methyltransferase DIM-2 and HP1 Is Required for DNA Methylation in Neurospora crassa

2008 ◽  
Vol 28 (19) ◽  
pp. 6044-6055 ◽  
Author(s):  
Shinji Honda ◽  
Eric U. Selker
Keyword(s):  
Dna Methylation ◽  
Neurospora Crassa ◽  
Dna Methyltransferase ◽  
Direct Interaction ◽  
Stable Complex ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Chromo Shadow Domain ◽  
Two Hybrid

ABSTRACT DNA methylation is involved in gene silencing and genomic stability in mammals, plants, and fungi. Genetics studies of Neurospora crassa have revealed that a DNA methyltransferase (DIM-2), a histone H3K9 methyltransferase (DIM-5), and heterochromatin protein 1 (HP1) are required for DNA methylation. We explored the interrelationships of these components of the methylation machinery. A yeast two-hybrid screen revealed that HP1 interacts with DIM-2. We confirmed the interaction in vivo and demonstrated that it involves a pair of PXVXL-related motifs in the N-terminal region of DIM-2 and the chromo shadow domain of HP1. Both regions are essential for proper DNA methylation. We also determined that DIM-2 and HP1 form a stable complex independently of the trimethylation of histone H3K9, although the association of DIM-2 with its substrate sequences depends on trimethyl-H3K9. The DIM-2/HP1 complex does not include DIM-5. We conclude that DNA methylation in Neurospora is largely or exclusively the result of a unidirectional pathway in which DIM-5 methylates histone H3K9 and then the DIM-2/HP1 complex recognizes the resulting trimethyl-H3K9 mark via the chromo domain of HP1.

scholarly journals HP1β Chromo Shadow Domain facilitates H2A ubiquitination for BRCA1 recruitment at DNA double-strand breaks

2022 ◽  
Author(s):  
Tej Pandita ◽  
Vijay Kumari Charaka ◽  
Sharmistha Chakraborty ◽  
Chi-Lin Tsai ◽  
Xiaoyan Wang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genome Stability ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Damage Repair ◽  
Dna Double Strand Break ◽  
Assembly Factor ◽  
Chromo Shadow Domain

Efficient DNA double strand break (DSB) repair by homologous recombination (HR), as orchestrated by histone and non-histone proteins, is critical to genome stability, replication, transcription, and cancer avoidance. Here we report that Heterochromatin Protein1 beta (HP1β) acts as a key component of the HR DNA resection step by regulating BRCA1 enrichment at DNA damage sites, a function largely dependent on the HP1β chromo shadow domain (CSD). HP1β itself is enriched at DSBs within gene-rich regions through a CSD interaction with Chromatin Assembly Factor 1 (CAF1) and HP1β depletion impairs subsequent BRCA1 enrichment. An added interaction of the HP1β CSD with the Polycomb Repressor Complex 1 ubiquitinase component RING1A facilitates BRCA1 recruitment by increasing H2A lysine 118-119 ubiquitination, a marker for BRCA1 recruitment. Our findings reveal that HP1β interactions, mediated through its CSD with RING1A, promote H2A ubiquitination and facilitate BRCA1 recruitment at DNA damage sites, a critical step in DSB repair by the HR pathway. These collective results unveil how HP1β is recruited to DSBs in gene-rich regions and how HP1β subsequently promotes BRCA1 recruitment to further HR DNA damage repair by stimulating CtIP-dependent resection.

scholarly journals Mitotic centromeric targeting of HP1 and its binding to Sgo1 are dispensable for sister-chromatid cohesion in human cells

2011 ◽  
Vol 22 (8) ◽  
pp. 1181-1190 ◽  
Author(s):  
Jungseog Kang ◽  
Jaideep Chaudhary ◽  
Hui Dong ◽  
Soonjoung Kim ◽  
Chad A. Brautigam ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
Human Cells ◽  
Structural Studies ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Chromatid Cohesion ◽  
A Subunit ◽  
Chromosome Passenger Complex ◽  
Chromo Shadow Domain

Human Shugoshin 1 (Sgo1) protects centromeric sister-chromatid cohesion during prophase and prevents premature sister-chromatid separation. Heterochromatin protein 1 (HP1) has been proposed to protect centromeric sister-chromatid cohesion by directly targeting Sgo1 to centromeres in mitosis. Here we show that HP1α is targeted to mitotic centromeres by INCENP, a subunit of the chromosome passenger complex (CPC). Biochemical and structural studies show that both HP1–INCENP and HP1–Sgo1 interactions require the binding of the HP1 chromo shadow domain to PXVXL/I motifs in INCENP or Sgo1, suggesting that the INCENP-bound, centromeric HP1α is incapable of recruiting Sgo1. Consistently, a Sgo1 mutant deficient in HP1 binding is functional in centromeric cohesion protection and localizes normally to centromeres in mitosis. By contrast, INCENP or Sgo1 mutants deficient in HP1 binding fail to localize to centromeres in interphase. Therefore, our results suggest that HP1 binding by INCENP or Sgo1 is dispensable for centromeric cohesion protection during mitosis of human cells, but might regulate yet uncharacterized interphase functions of CPC or Sgo1 at the centromeres.

Early stage of nucleic acid electrochemistry. Detection of DNA damage in X-ray-irradiated rats

2011 ◽  
Vol 76 (12) ◽  
pp. 1799-1810 ◽  
Author(s):  
Emil Paleček
Keyword(s):  
Dna Damage ◽  
Nucleic Acid ◽  
Dna Analysis ◽  
Early Stage ◽  
High Sensitivity ◽  
Strand Breaks ◽  
X Ray ◽  
Dna And Rna ◽  
Oscillographic Polarography ◽  
Radiation Induced

First papers on electroactivity of DNA and RNA were published more then 50 years ago. For about 8 years oscillographic polarography at controlled a.c. (OP, proposed by J. Heyrovský already in 1941) was the method of choice for DNA analysis. Since approximately 1954 Robert Kalvoda developed OP for wide application in various fields. It is shown that already before 1960 it was possible to detect damage to DNA in X-ray-irradiated rats by means of OP. DNA samples from irradiated animals produced significantly larger OP anodic guanine signal indicating changes in the DNA structure. At present, radiation-induced strand breaks and damage to bases in DNA can be electrochemically detected at high sensitivity.

scholarly journals The genomic silencing of position-effect variegation in Drosophila melanogaster: interaction between the heterochromatin-associated proteins Su(var)3-7 and HP1

2000 ◽  
Vol 113 (23) ◽  
pp. 4253-4261 ◽  
Author(s):  
M. Delattre ◽  
A. Spierer ◽  
C.H. Tonka ◽  
P. Spierer
Keyword(s):  
Chromosomal Rearrangements ◽  
Position Effect ◽  
Pericentric Heterochromatin ◽  
Position Effect Variegation ◽  
Effect Variegation ◽  
Associated Proteins ◽  
Chromo Shadow Domain ◽  
Two Hybrid ◽  
Hp1 Proteins

Position-effect variegation results from mosaic silencing by chromosomal rearrangements juxtaposing euchromatin genes next to pericentric heterochromatin. An increase in the amounts of the heterochromatin-associated Su(var)3-7 and HP1 proteins augments silencing. Using the yeast two-hybrid protein interaction trap system, we have isolated HP1 using Su(var)3-7 as a bait. We have then delimited three binding sites on Su(var)3-7 for HP1. On HP1, the C-terminal moiety, including the chromo shadow domain, is required for interaction. In vivo, both proteins co-localise not only in heterochromatin, but also in a limited set of sites in euchromatin and at telomeres. When delocalised to the sites bound by the protein Polycomb in euchromatin, HP1 recruits Su(var)3-7. Finally, and in contrast with euchromatin genes, a decrease in the amounts of both proteins enhances variegation of the light gene, one of the few genetic loci mapped within pericentric heterochromatin. This body of data supports a direct link between Su(var)3-7 and HP1 in the genomic silencing of position-effect variegation.

6-Gingerol prevents MEHP-induced DNA damage in human umbilical vein endothelia cells

2016 ◽  
Vol 36 (11) ◽  
pp. 1177-1185 ◽  
Author(s):  
G Yang ◽  
X Gao ◽  
L Jiang ◽  
X Sun ◽  
X Liu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Umbilical Vein ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Human Umbilical Vein ◽  
Associated Proteins ◽  
Dna Strand ◽  
Umbilical Vein Endothelial Cells ◽  
Ethylhexyl Phthalate

Mono (2-ethylhexyl) phthalate (MEHP) is the principal metabolite of di (2-etylhexyl) phthalate, which is widely used as a plasticizer, especially in medical devices. MEHP has toxic effects on cardiovascular system. The aim of this study was to investigate the possibility that 6-gingerol may inhibit the oxidative DNA damage of MEHP in human umbilical vein endothelial cells (HUVECs) and the potential mechanism. The comet assay was used to monitor DNA strand breaks. We have shown that 6-gingerol significantly reduced the DNA strand breaks caused by MEHP. MEHP increased the levels of reactive oxygen species and malondialdehyde, decreased the level of glutathione and activity of superoxide dismutase, and altered the mitochondrial membrane potential. In addition, DNA damage-associated proteins (p53 and p-Chk2 (T68)) were significantly increased by the treatment of MEHP. Those effects can all be protected by 6-gingerol. The results firmly indicate that 6-gingerol may have a strong protective ability against the DNA damage caused by MEHP in HUVECs, and the mechanism may relate to the antioxidant activity.

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