18 Questions
Which human diseases are associated with mutations in NER genes according to the text?
Xeroderma pigmentosum (XP), Cockayne Syndrome (CS), and trichothiodystrophy (TTD)
What is a common characteristic of xeroderma pigmentosum (XP) and Cockayne Syndrome (CS)?
Increased sensitivity to sunlight
How many different NER genes can defects lead to xeroderma pigmentosum?
Seven
What is the main function of XPA and XPC in the NER process?
Recognition and excision
What type of breaks are readily repaired using the opposite strand as a template?
Single strand breaks (SSBs)
Which protein coats the single-strand break and protects it from breaking further?
$PARP1$ proteins
What is the role of DNA glycosylase in the BER pathway?
Excise the specific damaged base to generate an AP site
Which type of DNA glycosylase has both glycosylase and AP lyase activities?
Bifunctional DNA glycosylase
How does DNA glycosylase conduct a search for damaged bases on DNA duplexes?
By nonspecifically binding and sliding on the DNA
What is the initial step in the Nucleotide Excision Repair (NER) process?
Cleavage of the phosphodiester backbone
Which factors contribute to the global genomic NER (GG-NER) pathway?
DDB1/DDB2(XPE), HR23B/XPC, XPA/RPA
What distinguishes global genomic NER (GG-NER) from transcription-coupled NER (TC-NER)?
Mode of damage detection
Which proteins are required for the initial detection of DNA damage in transcriptionally active regions during Transcription-Coupled Repair (TCR)?
CSA, CSB, UVSSA
What is the role of the XPF/ERCC1 complex in the Nucleotide Excision Repair (NER) process?
Cleaving 22 nucleotides 5' to the damage
Which DNA repair process results in the formation of an AP site?
Base Excision Repair (BER)
What is the function of RPA in the Nucleotide Excision Repair (NER) pathway?
Remodeling the damaged site
Which proteins play a role in sealing the repaired DNA strand during Nucleotide Excision Repair (NER)?
Ligase anchored to PCNA
What is the final step after the excised oligonucleotide is resynthesized during Nucleotide Excision Repair (NER)?
Sealing by ligase anchored to PCNA
Explore the mechanism of DNA glycosylase in catalyzing damaged base-excision repair through the BER pathway. Learn how DNA glycosylase identifies and excises specific damaged bases, creating AP sites for further repair. Understand the role of bifunctional DNA glycosylases with glycosylase and AP lyase activities.
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