Page last updated: 2024-10-24

subtelomeric heterochromatin formation

Definition

Target type: biologicalprocess

The compaction of chromatin into heterochromatin at the subtelomeric region. [GOC:mah, PMID:10219245, PMID:26205977]

Subtelomeric heterochromatin, located at the ends of chromosomes, is a specialized chromatin structure characterized by its unique composition and role in genome stability and regulation. Its formation is a complex process involving various factors and steps:

1. **Repetitive DNA Sequences:** Subtelomeric regions are enriched in repetitive DNA sequences, such as telomeric repeats (TTAGGG)n, and other satellite DNA sequences. These repetitive sequences are highly prone to recombination and instability.

2. **Heterochromatin Proteins:** Specific proteins, including HP1α, HP1β, and HP1γ, are recruited to subtelomeric regions. These proteins act as structural components of heterochromatin and bind to methylated histone tails (H3K9me3) which are enriched in these regions.

3. **Histone Modifications:** Histone tails within subtelomeric regions undergo specific modifications, particularly H3K9 methylation. This methylation is catalyzed by histone methyltransferases (HMTs) like Suv39h1 and G9a.

4. **DNA Methylation:** In some organisms, DNA methylation also contributes to subtelomeric heterochromatin formation. DNA methyltransferases (DNMTs) modify cytosines within the repetitive sequences.

5. **Replication Timing:** Subtelomeric regions typically replicate late in S phase. This late replication timing contributes to their compacted and inaccessible nature.

6. **Nuclear Organization:** Subtelomeric regions are often clustered together in the nucleus, forming distinct domains called "telomere clusters." This clustering facilitates interactions between telomeres and other nuclear structures.

7. **Silencing of Gene Expression:** Subtelomeric heterochromatin is associated with silencing of genes located within these regions. This silencing is mediated by the compact and inaccessible nature of heterochromatin, which prevents transcription factors from accessing the DNA.

8. **Protection from DNA Damage:** Subtelomeric heterochromatin plays a crucial role in protecting chromosome ends from degradation and fusion. The compact structure provides a barrier against exonucleases and other DNA-damaging agents.

9. **Maintenance of Telomere Length:** Subtelomeric heterochromatin is involved in regulating telomere length. It acts as a barrier against the spread of telomere repeats, ensuring proper telomere maintenance.

10. **Regulation of Gene Expression:** While subtelomeric heterochromatin is primarily associated with gene silencing, it can also influence gene expression in nearby regions. This influence can involve spreading of silencing signals or the recruitment of regulatory factors.'
"

Proteins (4)

ProteinDefinitionTaxonomy
Histone-lysine N-methyltransferase EZH1A histone-lysine N-methyltransferase EZH1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q92800]Homo sapiens (human)
NAD-dependent protein deacetylase sirtuin-6An NAD-dependent protein deacylase sirtuin-6 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q8N6T7]Homo sapiens (human)
NAD-dependent protein deacetylase sirtuin-2An NAD-dependent protein deacetylase sirtuin-2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q8IXJ6]Homo sapiens (human)
Histone-lysine N-methyltransferase EZH2A histone-lysine N-methyltransferase EZH2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q15910]Homo sapiens (human)

Compounds (53)

CompoundDefinitionClassesRoles
niacinamidenicotinamide : A pyridinecarboxamide that is pyridine in which the hydrogen at position 3 is replaced by a carboxamide group.pyridine alkaloid;
pyridinecarboxamide;
vitamin B3
anti-inflammatory agent;
antioxidant;
cofactor;
EC 2.4.2.30 (NAD(+) ADP-ribosyltransferase) inhibitor;
EC 3.5.1.98 (histone deacetylase) inhibitor;
Escherichia coli metabolite;
geroprotector;
human urinary metabolite;
metabolite;
mouse metabolite;
neuroprotective agent;
Saccharomyces cerevisiae metabolite;
Sir2 inhibitor
pyrazinamidepyrazinecarboxamide : A monocarboxylic acid amide resulting from the formal condensation of the carboxy group of pyrazinoic acid (pyrazine-2-carboxylic acid) with ammonia. A prodrug for pyrazinoic acid, pyrazinecarboxamide is used as part of multidrug regimens for the treatment of tuberculosis.monocarboxylic acid amide;
N-acylammonia;
pyrazines
antitubercular agent;
prodrug
pyrazinoic acidpyrazine-2-carboxylic acid : The parent compound of the class of pyrazinecarboxylic acids, that is pyrazine bearing a single carboxy substituent. The active metabolite of the antitubercular drug pyrazinamide.

pyrazinoic acid: active metabolite of pyrazinamide; structure
pyrazinecarboxylic acidantitubercular agent;
drug metabolite
bisindolylmaleimide ibisindolylmaleimide I: a bis(indolyl)maleimide
2-(1-(2-(1-methylpyrrolidino)ethyl)-1h-indol-3-yl)maleimidebisindolylmaleimide II: protein kinase C inhibitor; see also bisindolylmaleimide I
bisindolylmaleimide ivindoles;
maleimides
bisindolylmaleimide vbisindolylmaleimide V: used as a negative control compound for protein kinase C inhibition; structure in first source;indoles
go 6976indolocarbazole;
organic heterohexacyclic compound
EC 2.7.11.13 (protein kinase C) inhibitor
idebenone1,4-benzoquinones;
primary alcohol
antioxidant;
ferroptosis inhibitor
nsc 664704kenpaullone : An indolobenzazepine that is paullone in which the hydrogen at position 9 is replaced by a bromo substituent. It is an ATP-competitive inhibitor of cyclin-dependent kinases (CDKs) and glycogen synthase kinase 3beta (GSK3beta).

kenpaullone: inhibits CDK1/cyclin B; structure in first source
indolobenzazepine;
lactam;
organobromine compound
cardioprotective agent;
EC 2.7.11.22 (cyclin-dependent kinase) inhibitor;
EC 2.7.11.26 (tau-protein kinase) inhibitor;
geroprotector
fenamic acidfenamic acid : An aminobenzoic acid that is the N-phenyl derivative of anthranilic acid. It acts as a parent skeleton for the synthesis of several non-steroidal anti-inflammatory drugs.

fenamic acid: has chloride and potassium channel-blocking activity; RN given refers to parent cpd
aminobenzoic acid;
secondary amino compound
membrane transport modulator
ro 31-8220Ro 31-8220: a protein kinase C inhibitorimidothiocarbamic ester;
indoles;
maleimides
EC 2.7.11.13 (protein kinase C) inhibitor
fenofibratebenzochromenone;
delta-lactone;
naphtho-alpha-pyrone
platelet aggregation inhibitor;
Sir2 inhibitor
suraminsuramin : A member of the class of phenylureas that is urea in which each of the amino groups has been substituted by a 3-({2-methyl-5-[(4,6,8-trisulfo-1-naphthyl)carbamoyl]phenyl}carbamoyl)phenyl group. An activator of both the rabbit skeletal muscle RyR1 and sheep cardiac RyR2 isoform ryanodine receptor channels, it has been used for the treatment of human African trypanosomiasis for over 100 years.

Suramin: A polyanionic compound with an unknown mechanism of action. It is used parenterally in the treatment of African trypanosomiasis and it has been used clinically with diethylcarbamazine to kill the adult Onchocerca. (From AMA Drug Evaluations Annual, 1992, p1643) It has also been shown to have potent antineoplastic properties.
naphthalenesulfonic acid;
phenylureas;
secondary carboxamide
angiogenesis inhibitor;
antinematodal drug;
antineoplastic agent;
apoptosis inhibitor;
EC 2.7.11.13 (protein kinase C) inhibitor;
GABA antagonist;
GABA-gated chloride channel antagonist;
purinergic receptor P2 antagonist;
ryanodine receptor agonist;
trypanocidal drug
suramin sodiumsuramin sodium : An organic sodium salt that is the hexasodium salt of suramin. It is an FDA approved drug for African sleeping sickness and river blindness.organic sodium saltangiogenesis inhibitor;
antinematodal drug;
antineoplastic agent;
apoptosis inhibitor;
EC 2.7.11.13 (protein kinase C) inhibitor;
GABA antagonist;
GABA-gated chloride channel antagonist;
purinergic receptor P2 antagonist;
ryanodine receptor agonist;
trypanocidal drug
toxoflavintoxoflavin : A pyrimidotriazine that is 1,6-dimethyl-1,5,6,7-tetrahydropyrimido[5,4-e][1,2,4]triazine with oxo groups at positions 5 and 7.

toxoflavin: azapteridine antibiotic; structure
carbonyl compound;
pyrimidotriazine
antibacterial agent;
antineoplastic agent;
apoptosis inducer;
bacterial metabolite;
toxin;
virulence factor;
Wnt signalling inhibitor
3-deazaneplanocin3-deazaneplanocin: S-adenosylhomocysteine hydrolase antagonist
1-(4-nitrophenyl)piperazine1-(4-nitrophenyl)piperazine: structure in first source
tanshinonetanshinone: from root of Salvia miltiorrhiza Bunge; RN given refers to tanshinone I; cardioprotective agent and neuroprotective agentabietane diterpenoidanticoronaviral agent
rubimaillinrubimaillin : A benzochromene that is 2H-benzo[h]chromene which is substituted by two methyl groups at position 2, a methoxycarbonyl group at position 5, and a hydroxy group at position 6. Found in the Chinese medical plant Rubia cordifola, It has an anti-cancer effect by inhibition of TNF-alpha-induced NF-kappaB activation. It is also a dual inhibitor of acyl-CoA:cholesterol acyltransferase 1 and 2 (ACAT1 and ACAT2), but is more selective for the ACAT2 isozyme.

rubimaillin: structure given in first source
benzochromene;
methyl ester;
phenols
acyl-CoA:cholesterol acyltransferase 2 inhibitor;
anti-inflammatory agent;
antineoplastic agent;
apoptosis inducer;
neuroprotective agent;
NF-kappaB inhibitor;
plant metabolite
przewaquinone dprzewaquinone D: isolated from root of Salvia przewalskii; structure given in first source; RN given refers to the trans- isomer, przewaquinone D
tanshinone ii atashinone IIA: a cardiovascular agent with antineoplastic activity; isolated from Salvia miltiorrhiza; structure in first sourceabietane diterpenoid
5-chloropyrazinamide
paullonepaullone : An indolobenzazepine that is 5,6,7,12-tetrahydroindolo[3,2-d][1]benzazepine carrying an oxo substituent at position 6.

paullone: structure in first source
indolobenzazepine;
lactam
EC 2.7.11.22 (cyclin-dependent kinase) inhibitor;
EC 2.7.11.26 (tau-protein kinase) inhibitor
s-adenosylhomocysteineS-adenosyl-L-homocysteine : An organic sulfide that is the S-adenosyl derivative of L-homocysteine.

S-Adenosylhomocysteine: 5'-S-(3-Amino-3-carboxypropyl)-5'-thioadenosine. Formed from S-adenosylmethionine after transmethylation reactions.
adenosines;
amino acid zwitterion;
homocysteine derivative;
homocysteines;
organic sulfide
cofactor;
EC 2.1.1.72 [site-specific DNA-methyltransferase (adenine-specific)] inhibitor;
EC 2.1.1.79 (cyclopropane-fatty-acyl-phospholipid synthase) inhibitor;
epitope;
fundamental metabolite
hyperforinhyperforin : A cyclic terpene ketone that is a prenylated carbobicyclic acylphloroglucinol derivative produced by St. John's Wort, Hypericum perforatum.

hyperforin: a prenylated acylphloroglucinol derivative; antibiotic component of novoimanine; psychoactive agent in St. John's wort; Russian; structure;
trichostatin atrichostatin A: chelates zinc ion in the active site of histone deacetylases, resulting in preventing histone unpacking so DNA is less available for transcription; do not confuse with TRICHOSANTHIN which is a protein; found in STREPTOMYCESantibiotic antifungal agent;
hydroxamic acid;
trichostatin
bacterial metabolite;
EC 3.5.1.98 (histone deacetylase) inhibitor;
geroprotector
resveratroltrans-resveratrol : A resveratrol in which the double bond has E configuration.resveratrolantioxidant;
phytoalexin;
plant metabolite;
quorum sensing inhibitor;
radical scavenger
(3R,5S)-fluvastatin(3R,5S)-fluvastatin : A (6E)-7-[3-(4-fluorophenyl)-1-(propan-2-yl)-1H-indol-2-yl]-3,5-dihydroxyhept-6-enoic acid diastereoisomer in which the stereocentres beta- and delta- to the carboxy group have R and S configuration, respectively. The drug fluvastatin is an equimolar mixture of this compound and its enantiomer.(6E)-7-[3-(4-fluorophenyl)-1-(propan-2-yl)-1H-indol-2-yl]-3,5-dihydroxyhept-6-enoic acid;
statin (synthetic)
3-(1-azepanylsulfonyl)-n-(3-bromphenyl)benzamide3-(1-azepanylsulfonyl)-N-(3-bromphenyl)benzamide: a sirtuin 2 inhibitor; structure in first source
1,4-bis[2-(4-hydroxyphenyl)ethylamino]anthracene-9,10-dioneanthraquinone
sirtinolaldimine;
benzamides;
naphthols
anti-inflammatory agent;
EC 3.5.1.98 (histone deacetylase) inhibitor;
Sir2 inhibitor
cambinolcambinol: inhibitor of human silent information regulator 2 enzymes; structure in first source
(4-chlorophenyl)-[4-(8-nitro-5-quinolinyl)-1-piperazinyl]methanoneN-arylpiperazine
ex 5276-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide : A member of the class of carbazoles that is 2,3,4,9-tetrahydro-1H-carbazole which is substituted at position 1 by an aminocarbohyl group and at position 6 by a chlorine.

6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide: structure in first source
carbazoles;
monocarboxylic acid amide;
organochlorine compound
scutellareinscutellarein : Flavone substituted with hydroxy groups at C-4', -5, -6 and -7.

scutellarein: aglycone of scutellarin from Scutellaria baicalensis; carthamidin is 2S isomer of scutellarein; do not confuse with isoscutellarein and/or isocarthamidin which are respective regioisomers, or with the scutelarin protein
tetrahydroxyflavonemetabolite
su 11248monocarboxylic acid amide;
pyrroles
angiogenesis inhibitor;
antineoplastic agent;
EC 2.7.10.1 (receptor protein-tyrosine kinase) inhibitor;
immunomodulator;
neuroprotective agent;
vascular endothelial growth factor receptor antagonist
panobinostatpanobinostat : A hydroxamic acid obtained by formal condensation of the carboxy group of (2E)-3-[4-({[2-(2-methylindol-3-yl)ethyl]amino}methyl)phenyl]prop-2-enoic acid with the amino group of hydroxylamine. A histone deacetylase inhibitor used (as its lactate salt) in combination with bortezomib and dexamethasone for the treatment of multiple myeloma.

Panobinostat: An indole and hydroxamic acid derivative that acts as a HISTONE DEACETYLASE inhibitor. It is used as an antineoplastic agent in combination with BORTEZOMIB and DEXAMETHASONE for the treatment of MULTIPLE MYELOMA.
cinnamamides;
hydroxamic acid;
methylindole;
secondary amino compound
angiogenesis modulating agent;
antineoplastic agent;
EC 3.5.1.98 (histone deacetylase) inhibitor
oblongifolin coblongifolin C: has antineoplastic activity; isolated from Garcinia yunnanensis; structure in first source
quisinostatindoles
srt1460SRT1460: small molecule activator of SIRT1 as therapeutics for the treatment of type 2 diabetes; structure in first source
srt1720
srt2183SRT2183: small molecule activator of SIRT1 as therapeutics for the treatment of type 2 diabetes; structure in first source
tenovin-6tenovin-6 : A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 5-(dimethylamino)pentanoic acid with the aromatic amino group of N-[(4-aminophenyl)carbamothioyl]-4-tert-butylbenzamide.monocarboxylic acid amide;
tertiary amino compound;
thioureas
antineoplastic agent;
p53 activator;
Sir2 inhibitor
ly2784544pyridazines
acy-1215ricolinostat: an HDAC6 inhibitor; structure in first sourcepyrimidinecarboxylic acid
epz005687EPZ005687: inhibits EZH2 protein; structure in first sourceindazoles
epz-6438tazemetostat: a histone methyltransferase EZH2 inhibitor with antineoplastic activity
gsk-2816126GSK-2816126: inhibits EZH2 methyltransferase; structure in first sourcepiperazines;
pyridines
gsk343GSK343 : A member of the class of indazoles that is 1-isopropyl-1H-indazole-4-carboxamide in which the nitrogen of the carboxamide group is substituted by a (6-methyl-2-oxo-4-propyl-1,2-dihydropyridin-3-yl)methyl group and in which the indazole ring is substituted at position 6 by a 2-(4-methylpiperazin-1-yl)pyridin-4-yl group. A highly potent and selective EZH2 inhibitor (IC50 = 4 nM).

GSK343: an EZH2 methyltransferase inhibitor
aminopyridine;
indazoles;
N-alkylpiperazine;
N-arylpiperazine;
pyridone;
secondary carboxamide
antineoplastic agent;
apoptosis inducer;
EC 2.1.1.43 (enhancer of zeste homolog 2) inhibitor
1-[(1R)-1-(1-ethylsulfonyl-4-piperidinyl)ethyl]-N-[(4-methoxy-6-methyl-2-oxo-1H-pyridin-3-yl)methyl]-2-methyl-3-indolecarboxamide(R)-1-(1-(1-(ethylsulfonyl)piperidin-4-yl)ethyl)-N-((4-methoxy-6-methyl-2-oxo-1,2-dihydropyridin-3-yl)methyl)-2-methyl-1H-indole-3-carboxamide: EZH2 inhibitorindolecarboxamide
aristoforinAristoforin: derivative of hyperforin, is a potent anticancer agent; structure in first source
n-(3-((2-hydroxynaphthalen-1-ylmethylene)amino)phenyl)-2-phenylpropionamide