00:01
Hello students, p53 is a nuclear transcription factor with a pro -apoptotic function.
00:08
Since over 50 % of human cancers carry loss of function mutations in p53 chain, p53 has been considered to one of the classical type of the tumor suppressor.
00:22
Mutant p53 acts as the dominant negative inhibitor towards wild type p53.
00:27
So we will understand the working of this p53.
00:32
Let's say this is the cell and in this there is the nucleus and there is a lesion in the dna due to let's say uv radiation.
00:44
So this is the dna due to uv radiation there is lesion in this dna.
00:52
So there is a molecule known as atr which will sense this lesion then this atr will activate the checkpoint kinase 1.
01:08
Further this checkpoint kinase 1 will activate p53.
01:15
Under normal condition when there is no such damage to the dna during that condition p53 is inactive as it has binded to mdm2 but when there is such damage this chk1 will phosphorylate this p53 and it will make it active and this mdm2 will get inactive.
01:46
Further this p53 will regulate up regulate the further regulation that is it will activate the transcriptional target that is p21...