Thursday, July 31, 2014

XPD / ERCC2 ..... Official Name

Official Name:  Excision repair cross-complementation group 2
Official Symbol: ERCC2 
Other Names:
Ê basic transcription factor 2 80 kDa subunit
Ê BTF2 p80
Ê COFS2
Ê CXPD
Ê DNA excision repair protein ERCC-2
Ê DNA repair protein complementing XP-D cells
Ê EM9
Ê ERCC2_HUMAN
Ê excision repair cross-complementing rodent repair deficiency, complementation group 2
Ê MAG
Ê MGC102762
Ê MGC126218
Ê MGC126219
Ê TFIIH
Ê TFIIH 80 kDa subunit
Ê TFIIH basal transcription factor complex 80 kDa subunit
Ê TFIIH basal transcription factor complex helicase subunit
Ê TFIIH p80
Ê TTD
Ê xeroderma pigmentosum complementary group D
Ê xeroderma pigmentosum group D-complementing protein

Ê XPD


Wednesday, July 23, 2014

How XPC gene related to health cause XP .....

Xeroderma Pigmentosum (XP) is caused by mutations in the XPC gene. More than 40 mutations in the XPC gene have been found to cause Xeroderma Pigmentosum. Mutations in this gene are the most common cause of this disorder in the United States and Europe.

Most XPC gene mutations prevent the production of any XPC protein. A loss of this protein keeps cells from repairing DNA damage normally. As a result, abnormalities accumulate in DNA, causing cells to malfunction and eventually to become cancerous or die. These problems with DNA repair cause people with XP to be extremely sensitive to UV rays from sunlight. When UV rays damage genes that control cell growth and division, cells can grow too fast in an uncontrolled way. As a result, people with XP  have a greatly increased risk of developing cancer. These cancers occur most frequently in areas of the body that are exposed to the sun, such as the skin and eyes.


Unlike some of the other forms of Xeroderma Pigmentosum (XP), when the disorder is caused by mutations in the XPC gene it is generally not associated with neurological abnormalities (such as delayed development and hearing loss). It is unclear why some people with XP develop neurological abnormalities and others do not.


Tuesday, July 22, 2014

Normal Function of the XPC gene …..

The XPC gene provides instructions for making a protein which is involved in repairing damaged DNA ¾ DNA can be damaged by ultraviolet (UV) rays from the sun and by toxic chemicals, radiation, and unstable molecules called free radicals.

As we already know that DNA damage occurs frequently, but normal cells are usually able to fix it before it can cause problems ¾ one of the major mechanisms to fix DNA is known as nucleotide excision repair (NER). The XPC protein starts this repair process by detecting DNA damage. Then a group (complex) of other proteins unwinds the section of DNA where the damage has occurred, snip out (excise) the abnormal section and replace the damaged area with the correct DNA.

Studies suggest that the XPC protein may have additional roles in DNA repair and in other cell activities. Very less is known about the proposed functions of the XPC protein.


Monday, July 21, 2014

XPC ... Location

Cytogenetic Location: 3p25
Molecular Location: Chromosome 3
                           base pairs 14,145,146 ~ 14,178,671



The XPC gene is located on the short (p) arm of chromosome 3 at position 25 from base pair 14,145,146 ~ 14,178,671.


Sunday, July 20, 2014

XPC ... Official Name

Official Name:  Xeroderma Pigmentosum, complementation group C
Official Symbol: XPC

Other Names:
Ê RAD4
Ê Xeroderma pigmentosum group C-complementing protein
Ê XP3
Ê XPCC
Ê XPC_HUMAN


Saturday, July 19, 2014

How XPA gene cause Xeroderma Pigmentosum…..

Xeroderma Pigmentosum (XP) is caused by mutations in the XPA gene. At least 25 mutations in the XPA gene have been found to cause Xeroderma Pigmentosum. Mutations in this gene are responsible for a very severe form of the disorder that is more common in the Japanese population than in other populations. Most Japanese people with Xeroderma Pigmentosum have the same XPA gene mutation, which is written as IVS3AS, G>C. This mutation prevents cells from producing any functional XPA protein. Other XPA gene mutations, which have been reported in Japan and elsewhere, result in the production of a defective version of the XPA protein or greatly reduce the amount of this protein that is made in cells.

A partial or complete loss of the XPA protein prevents cells from repairing DNA damage normally. As a result, abnormalities accumulate in DNA, causing cells to malfunction and eventually to become cancerous or die. These problems with DNA repair cause people with Xeroderma Pigmentosum (XP) to be extremely sensitive to UV rays from sunlight. When UV rays damage genes that control cell growth and division, cells can grow too fast and in an uncontrolled way. As a result, people with XP have a greatly increased risk of developing cancer. These cancers occur most frequently in areas of the body that are exposed to the sun, such as the skin and eyes.

When XP is caused by XPA gene mutations, it is often associated with progressive neurological abnormalities. These nervous system problems include hearing loss, poor coordination, difficulty walking, movement problems, loss of intellectual function, difficulty swallowing and talking, and seizures. The neurological abnormalities are thought to result from a buildup of DNA damage, although the brain is not exposed to UV rays.


Researchers suspect that other factors damage DNA in nerve cells. It is unclear why some people with Xeroderma Pigmentosum develop neurological abnormalities and others do not.



Wednesday, July 16, 2014

Function of the XPA gene …..

The XPA gene provides instructions for making a protein which repairs damaged DNA ¾ DNA can be damaged by ultraviolet (UV) rays from the sun and by toxic chemicals, radiation, and unstable molecules called free radicals. DNA damage occurs frequently, but normal cells are usually able to fix it before it can cause problems. One of the major mechanisms that cells use to fix DNA is known as nucleotide excision repair (NER). As part of this repair mechanism, the XPA protein helps verify DNA damage and stabilize the DNA as it is repaired. The XPA protein binds (attach) to areas of damaged DNA, where it interacts with many other proteins as part of a large complex mechanism. Proteins in this complex unwind the section of DNA where the damage has occurred, snip out (excise) the abnormal section, and replace the damaged area with the correct DNA.