XPG

Definition

XPG is a crucial protein involved in the DNA repair process, specifically in nucleotide excision repair (NER). It functions as a 3' exonuclease, helping to remove damaged DNA segments by cleaving the DNA strand at the site of damage, which is essential for maintaining genomic integrity. XPG plays a key role in recognizing and excising bulky DNA adducts, allowing the repair machinery to restore the DNA to its correct sequence.

5 Must Know Facts For Your Next Test

1. XPG is part of the larger NER complex that includes other proteins such as XPA, XPB, XPC, and XPF, which work together to identify and repair DNA lesions.
2. Deficiencies in XPG can lead to Xeroderma Pigmentosum, a genetic disorder characterized by extreme sensitivity to UV radiation and a higher risk of skin cancers.
3. XPG specifically cleaves damaged DNA at sites located 3' to the lesion, making it essential for the proper functioning of the NER pathway.
4. The activity of XPG is regulated by several factors, including post-translational modifications that can affect its stability and function during the DNA repair process.
5. Research has shown that XPG may also have roles beyond DNA repair, including involvement in transcription regulation and cell cycle control.

Review Questions

• How does XPG contribute to the process of nucleotide excision repair, and why is this process important for cellular health?
  • XPG contributes to nucleotide excision repair by acting as a 3' exonuclease that helps remove damaged segments of DNA. This is important because it allows cells to repair harmful lesions caused by environmental factors like UV radiation, which can lead to mutations if left uncorrected. By facilitating the excision of damaged DNA, XPG ensures the integrity of the genome and prevents the accumulation of mutations that could cause diseases such as cancer.
• Discuss the consequences of XPG deficiencies on human health, particularly in relation to genetic disorders.
  • Deficiencies in XPG can result in Xeroderma Pigmentosum (XP), a severe genetic disorder marked by heightened sensitivity to UV light. Individuals with XP have a significantly increased risk of developing skin cancers due to their inability to efficiently repair UV-induced DNA damage. This condition highlights the critical role that XPG plays in maintaining genomic integrity and protecting against mutagenesis caused by environmental factors.
• Evaluate the broader implications of XPG's functions beyond DNA repair, considering its potential roles in other cellular processes.
  • XPG's functions extend beyond just DNA repair; it may also play roles in transcription regulation and cell cycle control. Understanding these additional functions could provide insights into how cells respond to stress and maintain homeostasis under various conditions. As research progresses, uncovering these multifaceted roles of XPG could lead to new therapeutic approaches for diseases linked to both genomic instability and cellular regulation, highlighting its significance in cellular biology.

Related terms

Nucleotide Excision Repair: A DNA repair mechanism that removes and replaces damaged sections of DNA, particularly those caused by UV light and chemical exposure.

Exonuclease: An enzyme that removes nucleotide units from the end of a nucleic acid molecule, playing an important role in processes like DNA repair and replication.

Genomic Integrity: The overall stability and correctness of an organism's genetic information, which is crucial for normal cellular function and development.