1. Activation of DNA damage response pathways: DNA damage triggers the activation of DNA damage response pathways, such as the ATM (ataxia-telangiectasia mutated) and ATR (ataxia-telangiectasia and Rad3-related) pathways. These pathways lead to the phosphorylation of various proteins, including the transcription factors p53 and BRCA1.
2. Transcriptional arrest: DNA damage can cause the arrest of ongoing transcription. This is achieved by the phosphorylation of RNA polymerase II by the ATM and ATR pathways. Phosphorylation of RNA polymerase II inhibits its activity and leads to the dissociation of the transcription machinery from the DNA template.
3. Induction of DNA damage-responsive genes: DNA damage induces the transcription of a specific set of genes known as DNA damage-responsive genes. These genes are involved in DNA repair, cell cycle checkpoint control, and apoptosis. The transcription of these genes is often mediated by the activated transcription factors p53 and BRCA1.
4. Changes in chromatin structure: DNA damage can induce changes in chromatin structure, which can affect gene transcription. For example, DNA damage can lead to the formation of DNA double-strand breaks, which can disrupt the normal structure of chromatin and make it inaccessible to the transcription machinery.
Overall, DNA damage causes a complex and dynamic response in gene transcription, which is essential for maintaining genome integrity and preventing cell death.
