The ERCC3 gene
helps in making a protein called XPB. XPB is an essential subunit of a group of
proteins known as the general transcription factor IIH (TFIIH) complex.
The TFIIH complex has two major functions:
I.
It involves in
a process of gene transcription
II.
It helps
repair damaged DNA.
Gene transcription is
the first step in protein production. By controlling gene transcription, the
TFIIH complex helps regulate the activity of many different genes. Research suggest
that the XPB protein works together with XPD, another protein in the TFIIH
complex that is produced from the ERCC2 gene, to initiate gene
transcription.
The TFIIH complex
also plays an important role in repairing damaged DNA, which 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 usually fix the damage through nucleotide
excision repair (NER) mechanism before it can cause problems. As part of this
repair mechanism, the TFIIH complex unwinds the section of double-stranded DNA
that surrounds the damage. Studies suggest that the XPB protein may act as a
wedge, holding open the two strands of DNA so other proteins can snip out
(excise) the abnormal section and replace the damaged area with the correct
DNA.
Source: www.ghr.nlm.nih.gov
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