Page last updated: 2024-10-24

rDNA heterochromatin

Definition

Target type: cellularcomponent

A region of heterochromatin located at the rDNA repeats in a chromosome. [GOC:mah, PMID:20661445]

rDNA heterochromatin is a specialized type of chromatin that is found in the nucleolus, a subnuclear structure that is responsible for ribosome biogenesis. The nucleolus is composed of three main components: the fibrillar center, the dense fibrillar component, and the granular component. rDNA heterochromatin is located primarily in the dense fibrillar component, where it is organized into a complex structure called the nucleolar organizer region (NOR). The NOR is a highly transcribed region of the genome that contains multiple copies of the genes that encode ribosomal RNA (rRNA). The rDNA genes are transcribed by RNA polymerase I, and the resulting rRNA transcripts are processed and assembled into ribosomes. rDNA heterochromatin is characterized by its highly repetitive nature, its dense packing, and its low level of gene expression. The repetitive nature of rDNA heterochromatin is due to the presence of multiple copies of the rDNA genes, which are clustered together in the NOR. The dense packing of rDNA heterochromatin is due to the presence of a variety of proteins that bind to the DNA and help to compact it. The low level of gene expression in rDNA heterochromatin is due to the fact that the rDNA genes are not actively transcribed in this region of the genome. rDNA heterochromatin plays an important role in the regulation of ribosome biogenesis. The dense packing of rDNA heterochromatin helps to prevent the transcription of rDNA genes that are not needed. In addition, the low level of gene expression in rDNA heterochromatin helps to ensure that rRNA is only produced when it is needed.'
"

Proteins (3)

ProteinDefinitionTaxonomy
Bromodomain adjacent to zinc finger domain protein 2AA bromodomain adjacent to zinc finger domain protein 2A that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UIF9]Homo sapiens (human)
NAD-dependent protein deacetylase sirtuin-1An NAD-dependent protein deacetylase sirtuin-1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q96EB6]Homo sapiens (human)
Histone-lysine N-methyltransferase SUV39H1A histone-lysine N-methyltransferase SUV39H1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O43463]Homo sapiens (human)

Compounds (39)

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
bisindolylmaleimide ibisindolylmaleimide I: a bis(indolyl)maleimide
bisindolylmaleimide vbisindolylmaleimide V: used as a negative control compound for protein kinase C inhibition; structure in first source;indoles
entinostatbenzamides;
carbamate ester;
primary amino compound;
pyridines;
substituted aniline
antineoplastic agent;
apoptosis inducer;
EC 3.5.1.98 (histone deacetylase) inhibitor
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
nadNADgeroprotector
gliotoxingliotoxin : A pyrazinoindole with a disulfide bridge spanning a dioxo-substituted pyrazine ring; mycotoxin produced by several species of fungi.

Gliotoxin: A fungal toxin produced by various species of Trichoderma, Gladiocladium fimbriatum, Aspergillus fumigatus, and Penicillium. It is used as an immunosuppressive agent.
dipeptide;
organic disulfide;
organic heterotetracyclic compound;
pyrazinoindole
antifungal agent;
EC 2.5.1.58 (protein farnesyltransferase) inhibitor;
immunosuppressive agent;
mycotoxin;
proteasome inhibitor
4-tert-butylbenzoic acid4-tert-butylbenzoic acid: RN given refers to parent cpdalkylbenzene
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
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;
surfactin csurfactin C : A cyclodepsipeptide that is N-[(3R)-3-hydroxy-13-methyltetradecanoyl]-L-alpha-glutamyl-L-leucyl-D-leucyl-L-valyl-L-alpha-aspartyl-D-leucyl-L-leucine in which the C-terminal carboxy group has been lactonised by condensation with the alcoholic hydroxy group.cyclodepsipeptide;
lipopeptide antibiotic;
macrocyclic lactone
antibacterial agent;
antifungal agent;
antineoplastic agent;
antiviral agent;
metabolite;
platelet aggregation inhibitor;
surfactant
resveratroltrans-resveratrol : A resveratrol in which the double bond has E configuration.resveratrolantioxidant;
phytoalexin;
plant metabolite;
quorum sensing inhibitor;
radical scavenger
CHIC-35CHIC-35 : An organic heterotricyclic compound resulting from the formal fusion of the 2-3 bond of 5-chloroindole with the 2-3 bond of cycloheptanecarboxamide (the S enantiomer). It is a potent, cell-permeable, metabolically stable and selective inhibitor of the deacetylase SIRT1.aromatic compound;
organic heterotricyclic compound;
organochlorine compound;
primary carboxamide
EC 3.5.1.98 (histone deacetylase) inhibitor
3-(1-azepanylsulfonyl)-n-(3-bromphenyl)benzamide3-(1-azepanylsulfonyl)-N-(3-bromphenyl)benzamide: a sirtuin 2 inhibitor; structure in first source
CAY10591CAY10591: a SIRT1 NAD-dependent histone deacetylase activatorquinoxaline derivative
sirtinolaldimine;
benzamides;
naphthols
anti-inflammatory agent;
EC 3.5.1.98 (histone deacetylase) inhibitor;
Sir2 inhibitor
verticillinsverticillins: 3 antibiotics isolated from imperfect fungus Verticillium: verticillin A, verticillin B (mono-3-hydroxymethyl analog of verticillin A), & verticillin C (differs from verticillin B in that 1 of dioxopiperazine rings has a trisulfide rather than a disulfide bridge; active against gram-positive bacteria & mycobacteria but not against gram-negative bacteria & fungi; RN given refers to cpd with unknown MF; structure (verticillins A & B))
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
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
chetomin
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
i-bet726
acy-1215ricolinostat: an HDAC6 inhibitor; structure in first sourcepyrimidinecarboxylic acid
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
aristoforinAristoforin: derivative of hyperforin, is a potent anticancer agent; structure in first source
n-(3-((2-hydroxynaphthalen-1-ylmethylene)amino)phenyl)-2-phenylpropionamide