p53

extremely unstable protein and generally does not accumulate to high enough levels to stimulate transcription under normal conditions

TLS Online TPP Program

#Id: 6139

#Unit 3. Fundamental Processes

In global genome repair (GG-NER), the XPC protein detects the damage and initiates the repair pathway. XPC can recognize damage anywhere in the genome. In mammals, XPC is a component of a lesion-sensing complex that also includes the proteins HR23B and centrin2.

TLS Online TPP Program

#Id: 6140

#Unit 3. Fundamental Processes

UV-induced cyclobutane pyrimidine dimers (CPDs), are not well recognized by XPC. In this case, the DNA damage-binding (DDB) complex assists in recruiting XPC to this type of damage.

TLS Online TPP Program

#Id: 6141

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6142

#Unit 3. Fundamental Processes

transcription-coupled repair (TC-NER) TFIIH, itself a large complex, which includes the products of two XP genes, XPB and XPD. 

TLS Online TPP Program

#Id: 6143

#Unit 3. Fundamental Processes

Cleavages are made on either side of the lesion by endonucleases encoded by the XPG and XPF genes. XPG is related to an endonuclease called FEN1 that cleaves DNA during the base excision repair pathway

TLS Online TPP Program

#Id: 6144

#Unit 3. Fundamental Processes

Finally, the single-stranded stretch including the damaged bases can then be replaced by new synthesis, and the final remaining nick is ligated by a complex of ligase III and XRCC1.