Microbial Genetics (Micr340) Lecture 14 DNA Repair and Mutagenesis.
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Transcript of Microbial Genetics (Micr340) Lecture 14 DNA Repair and Mutagenesis.
![Page 1: Microbial Genetics (Micr340) Lecture 14 DNA Repair and Mutagenesis.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649d785503460f94a5b03a/html5/thumbnails/1.jpg)
Microbial Genetics (Micr340)
Lecture 14DNA Repair and Mutagenesis
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Definitions
Lesion: chemical damage in DNA Mutagens: chemical compounds that
cause lesions in DNA which can kill cells and can also increase frequency of mutations in DNA
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Evidence for DNA repair
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Specific Repair Pathways
Repair of deaminated bases Damage due to reactive oxygen Alkylation of DNA and repair Pyrimidine dimer repair
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Base Deamination by nitrous acid
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Spontaneous Base Deamination
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Repair of altered bases by DNA glycosylases
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Damage due to reactive oxygen
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Mechanism of avoiding GO
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AlkylationOf guanine
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Repair of alkylated DNA
Specific N-glycosylases Methyltransferases
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PyrimidineDimer Formation
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Photoreactivation
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General Repair Mechanisms
Methyl-directed mismatch repair system
Nucleotide excision repair SOS inducible repair
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A model for methyl
Directed mismatch
repair
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A model for nucleotide excision repair
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SOS response
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SOS response
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Regulation of SOS mutagenesis in E. coli