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ERCC2
__NOTOC__ ERCC2, or XPD is a protein involved in transcription-coupled nucleotide excision repair. The XPD (ERCC2) gene encodes for a 2.3-kb mRNA containing 22 exons and 21 introns. The XPD protein contains 760 amino acids and is a polypeptide with a size of 87kDa. Defects in this gene can result in three different disorders: the cancer-prone syndrome xeroderma pigmentosum complementation group D, photosensitive trichothiodystrophy, and Cockayne syndrome. Just like XPB, XPD is a part of human transcriptional initiation factor TFIIH and has ATP-dependent helicase activity. It belongs to the RAD3/XPD subfamily of helicases. XPD is essential for the viability of cells. Deletion of XPD in mice is lethal for developing embryos. Consequences of mutations in ERCC2 The ERCC2/XPD protein participates in nucleotide excision repair and is used in unwinding the DNA double helix after damage is initially identified. Nucleotide excision repair is a multi-step pathway that removes a wide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription-coupled Nucleotide Excision Repair
Nucleotide excision repair is a DNA repair mechanism. DNA damage occurs constantly because of chemicals (e.g. intercalating agents), radiation and other mutagens. Three excision repair pathways exist to repair single stranded DNA damage: Nucleotide excision repair (NER), base excision repair (BER), and DNA mismatch repair (MMR). While the BER pathway can recognize specific non-bulky lesions in DNA, it can correct only damaged bases that are removed by specific glycosylases. Similarly, the MMR pathway only targets mismatched Watson-Crick base pairs. Nucleotide excision repair (NER) is a particularly important excision mechanism that removes DNA damage induced by ultraviolet light (UV). UV DNA damage results in bulky DNA adducts - these adducts are mostly thymine dimers and 6,4-photoproducts. Recognition of the damage leads to removal of a short single-stranded DNA segment that contains the lesion. The undamaged single-stranded DNA remains and DNA polymerase uses it as a temp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotide Excision Repair
Nucleotide excision repair is a DNA repair mechanism. DNA damage occurs constantly because of chemicals (e.g. intercalating agents), radiation and other mutagens. Three excision repair pathways exist to repair single stranded DNA damage: Nucleotide excision repair (NER), base excision repair (BER), and DNA mismatch repair (MMR). While the BER pathway can recognize specific non-bulky lesions in DNA, it can correct only damaged bases that are removed by specific glycosylases. Similarly, the MMR pathway only targets mismatched Watson-Crick base pairs. Nucleotide excision repair (NER) is a particularly important excision mechanism that removes DNA damage induced by ultraviolet light (UV). UV DNA damage results in bulky DNA adducts - these adducts are mostly thymine dimers and 6,4-photoproducts. Recognition of the damage leads to removal of a short single-stranded DNA segment that contains the lesion. The undamaged single-stranded DNA remains and DNA polymerase uses it as a templa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Damage Theory Of Aging
The DNA damage theory of aging proposes that aging is a consequence of unrepaired accumulation of naturally occurring DNA damage. Damage in this context is a DNA alteration that has an abnormal structure. Although both mitochondrial and nuclear DNA damage can contribute to aging, nuclear DNA is the main subject of this analysis. Nuclear DNA damage can contribute to aging either indirectly (by increasing apoptosis or cellular senescence) or directly (by increasing cell dysfunction). Several review articles have shown that deficient DNA repair, allowing greater accumulation of DNA damage, causes premature aging; and that increased DNA repair facilitates greater longevity. Mouse models of nucleotide-excision–repair syndromes reveal a striking correlation between the degree to which specific DNA repair pathways are compromised and the severity of accelerated aging, strongly suggesting a causal relationship. Human population studies show that single-nucleotide polymorphisms in D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xeroderma Pigmentosum
Xeroderma pigmentosum (XP) is a genetic disorder in which there is a decreased ability to repair DNA damage such as that caused by ultraviolet (UV) light. Symptoms may include a severe sunburn after only a few minutes in the sun, freckling in sun-exposed areas, dry skin and changes in skin pigmentation. Nervous system problems, such as hearing loss, poor coordination, loss of intellectual function and seizures, may also occur. Complications include a high risk of skin cancer, with about half having skin cancer by age 10 without preventative efforts, and cataracts. There may be a higher risk of other cancers such as brain cancers. XP is autosomal recessive, with mutations in at least nine specific genes able to result in the condition. Normally, the damage to DNA which occurs in skin cells from exposure to UV light is repaired by nucleotide excision repair. In people with xeroderma pigmentosum, this damage is not repaired. As more abnormalities form in DNA, cells malfunction and e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTF2H1
General transcription factor IIH subunit 1 is a protein that in humans is encoded by the ''GTF2H1'' gene. Interactions GTF2H1 has been shown to interact with: * Cyclin-dependent kinase 7, * E2F1, * ERCC2, * Estrogen receptor alpha, * TCEA1, and * XPB. See also * Transcription Factor II H Transcription factor II Human (transcription factor II H; TFIIH) is an important protein complex, having roles in transcription of various protein-coding genes and DNA nucleotide excision repair (NER) pathways. TFIIH first came to light in 1989 ... References Further reading * * * * * * * * * * * * * * * * * * External links * * {{NLM content Transcription factors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TFIIH
Transcription factor II Human (transcription factor II H; TFIIH) is an important protein complex, having roles in transcription of various protein-coding genes and DNA nucleotide excision repair (NER) pathways. TFIIH first came to light in 1989 when general transcription factor-δ or basic transcription factor 2 was characterized as an indispensable transcription factor in vitro. This factor was also isolated from yeast and finally named as TFIIH in 1992. TFIIH consists of ten subunits, 7 of which (ERCC2/XPD, ERCC3/XPB, GTF2H1/p62, GTF2H4/p52, GTF2H2/p44, GTF2H3/p34 and GTF2H5/TTDA) form the core complex. The cyclin activating kinase-subcomplex (CDK7, MAT1, and cyclin H) is linked to the core via the XPD protein. Two of the subunits, ERCC2/XPD and ERCC3/XPB, have helicase and ATPase activities and help create the transcription bubble. In a test tube these subunits are only required for transcription if the DNA template is not already denatured or if it is supercoiled. Two ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichothiodystrophy
Trichothiodystrophy (TTD) is an autosomal recessive inherited disorder characterised by brittle hair and intellectual impairment. The word breaks down into ''tricho'' – "hair", '' thio'' – "sulphur", and ''dystrophy'' – "wasting away" or literally "bad nourishment". TTD is associated with a range of symptoms connected with organs of the ectoderm and neuroectoderm. TTD may be subclassified into four syndromes: Approximately half of all patients with trichothiodystrophy have photosensitivity, which divides the classification into syndromes with or without photosensitivity; BIDS and PBIDS, and IBIDS and PIBIDS. Modern covering usage is TTD-P (photosensitive), and TTD. Presentation Features of TTD can include photosensitivity, ichthyosis, brittle hair and nails, intellectual impairment, decreased fertility and short stature. A more subtle feature associated with this syndrome is a "tiger tail" banding pattern in hair shafts, seen in microscopy under polarized light. The acronyms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTF2H2
General transcription factor IIH subunit 2 is a protein that in humans is encoded by the ''GTF2H2'' gene. Function This gene is part of a 500 kb inverted duplication on chromosome 5q13. This duplicated region contains at least four genes and repetitive elements which make it prone to rearrangements and deletions. The repetitiveness and complexity of the sequence have also caused difficulty in determining the organization of this genomic region. This gene is within the telomeric copy of the duplication. Deletion of this gene sometimes accompanies deletion of the neighboring SMN1 gene in spinal muscular atrophy (SMA) patients but it is unclear if deletion of this gene contributes to the SMA phenotype. This gene encodes the 44 kDa subunit of RNA polymerase II transcription initiation factor IIH which is involved in basal transcription and nucleotide excision repair. Transcript variants for this gene have been described, but their full length nature has not been determined. A second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicase
Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two hybridized nucleic acid strands (hence '' helic- + -ase''), using energy from ATP hydrolysis. There are many helicases, representing the great variety of processes in which strand separation must be catalyzed. Approximately 1% of eukaryotic genes code for helicases. The human genome codes for 95 non-redundant helicases: 64 RNA helicases and 31 DNA helicases. Many cellular processes, such as DNA replication, transcription, translation, recombination, DNA repair, and ribosome biogenesis involve the separation of nucleic acid strands that necessitates the use of helicases. Some specialized helicases are also involved in sensing of viral nucleic acids during infection and fulfill a immunological function. Function Helicases are o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excision Repair Cross-complementing
Excision repair cross-complementing (ERCC) is a set of proteins which are involved in DNA repair. In humans, ERCC proteins are transcribed from the following genes: ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, ERCC6, and ERCC8. Members 1 though 5 are associated with Xeroderma Pigmentosum. Members 6 and 8 are associated with Cockayne syndrome Cockayne syndrome (CS), also called Neill-Dingwall syndrome, is a rare and fatal autosomal recessive neurodegenerative disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosen .... References DNA repair {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ERCC5
DNA repair protein complementing XP-G cells is a protein that in humans is encoded by the ''ERCC5'' gene. Function Excision repair cross-complementing rodent repair deficiency, complementation group 5 (xeroderma pigmentosum, complementation group G) is involved in excision repair of UV-induced DNA damage. Mutations cause Cockayne syndrome, which is characterized by severe growth defects, mental retardation, and cachexia. Multiple alternatively spliced transcript variants encoding distinct isoforms have been described, but the biological validity of all variants has not been determined. Mutations in ERCC5 cause arthrogryposis. XPG is a structure specific endonuclease that incises DNA at the 3’ side of the damaged nucleotide during nucleotide excision repair. Syndromes Mutational defects in the ''Ercc5''(''Xpg'') gene can cause either the cancer-prone condition xeroderma pigmentosum (XP) alone, or in combination with the severe neurodevelopmental disorder Cockayne syndrome (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
