MSU & Skol. Tech DNA repair. DNA repair

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12._dna_repair.ppt

  • Количество слайдов: 31

>MSU & SkolTech DNA repair MSU & SkolTech DNA repair

>DNA repair DNA repair pathways Direct reversal 2. Base excision repair (BER) 3. Nucleotides DNA repair DNA repair pathways Direct reversal 2. Base excision repair (BER) 3. Nucleotides excision repair (NER) 4. Mismatch repair (MMR) 5. Trans-lesion synthesis (SOS-response) 6. Repair via recombination 7. Double strand break repair

>DNA repair Thymine dimer formation is the most frequent DNA lesion, formed at UV DNA repair Thymine dimer formation is the most frequent DNA lesion, formed at UV light exposure

>Direct reversal DNA photolyase Direct reversal DNA photolyase

>Direct reversal Mechanism of DNA photolyase action Direct reversal Mechanism of DNA photolyase action

>Direct reversal Alkylated nucleotide repair Direct reversal Alkylated nucleotide repair

>Direct reversal Ketoglutarate-dependent oxidation Direct reversal Ketoglutarate-dependent oxidation

>Base excision repair DNA glycosylases Substrate specificity 1. Deaminated bases (U, xantine, hypoxantin) 2. Base excision repair DNA glycosylases Substrate specificity 1. Deaminated bases (U, xantine, hypoxantin) 2. Oxidized bases (o8G) 3. Alkylated bases (m3A) Uracil DNA glycosylase

>Base excision repair DNA glycosylases Base excision repair DNA glycosylases

>Base excision repair Pathways in eukaryotes Base excision repair Pathways in eukaryotes

>Base excision repair Pathways in eukaryotes Base excision repair Pathways in eukaryotes

>Nucleotide excision repair NER in bacteria Nucleotide excision repair NER in bacteria

>Nucleotide excision repair UvrB –damage verification UvrA – primary recognition of damaged patch Nucleotide excision repair UvrB –damage verification UvrA – primary recognition of damaged patch

>Nucleotide excision repair Transcription coupled repair in bacteria Nucleotide excision repair Transcription coupled repair in bacteria

>Nucleotide excision repair NER in eukaryotic cells Nucleotide excision repair NER in eukaryotic cells

>Nucleotide excision repair NER in eukaryotic cells Nucleotide excision repair NER in eukaryotic cells

>Nucleotide excision repair NER in eukaryotic cells Nucleotide excision repair NER in eukaryotic cells

>Nucleotide excision repair Transcription coupled NER in eukaryotic cells Nucleotide excision repair Transcription coupled NER in eukaryotic cells

>Nucleotide excision repair NER defects in human leads to xeroderma pigmentosum and Cockayne syndrome Nucleotide excision repair NER defects in human leads to xeroderma pigmentosum and Cockayne syndrome

>Very short patch repair Competes and partially overlaps with MMR MMR is active during Very short patch repair Competes and partially overlaps with MMR MMR is active during replication, Vsp is active in stationary phase

>Mismatch repair Use semimethylated DNA to distinguish between parental and newly made DNA strands Mismatch repair Use semimethylated DNA to distinguish between parental and newly made DNA strands

>Mismatch repair MutS dimer recognize mismatch in DNA Mismatch repair MutS dimer recognize mismatch in DNA

>Mismatch repair How could mismatches located at 1000s nt from the dam site be Mismatch repair How could mismatches located at 1000s nt from the dam site be corrected? MutS transition to a sliding clamp

>Mismatch repair MMR in eukaryotes Mismatch repair MMR in eukaryotes

>SOS response RecA function in recombination and induce SOS response SOS response RecA function in recombination and induce SOS response

>SOS response Activated RecA cleaves LexA repressor SOS response Activated RecA cleaves LexA repressor

>SOS response Among other induced SOS response components DNAP V able to synthesize DNA SOS response Among other induced SOS response components DNAP V able to synthesize DNA through damaged DNA

>SOS response In eukaryiotic cells translesion DNA synthesis is activated at stalled replication fork SOS response In eukaryiotic cells translesion DNA synthesis is activated at stalled replication fork by monoubiquitination of PCNA

>Replication fork reversal Yet another opportunity for bypassing damaged DNA Replication fork reversal Yet another opportunity for bypassing damaged DNA

>Double strand break repair DSB recognition Double strand break repair DSB recognition

>Double strand break repair NHEJ Double strand break repair NHEJ