Term
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Definition
| produces protein necessary for phage integration |
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Term
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Definition
| produces protein necessary for phage excision |
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Term
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Definition
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Term
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Definition
| reversion that restores the original amino acid production by converting the mutant codon to a codon that codes for the original amino acid |
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Term
| Reading frame suppression |
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Definition
| Reversion that restores the reading frame (e.g., for one-NT insertion, either deleting one NT or adding two) |
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Term
| Distant compensatory suppression |
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Definition
| reversion with an extragenic mutation (ex., if a mutation added a stop, the tRNA anticodon could be mutated to carry the amino acid corresponding to the original mRNA codon) |
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Term
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Definition
| 3’ → 5’ exonuclease activity by polIII ε subunit |
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Term
| Light-dependent repair (photoreactivation) |
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Definition
| repair system; photolyases use energy from blue light to remove covalent bonds from pyrimidine dimers. |
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Term
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Definition
Repair system; replaces a single damaged nucleotide.
Glycosylase: excises the damaged base.
AP endonuclease and phosphodiesterase: removes the remaining sugar-phosphate at the AP site.
DNA polymerase: fills the gap using the undamaged complementary DNA strand as template.
DNA ligase: repairs the nick left by the polymerase. |
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Term
| Nucleotide excision repair |
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Definition
Repair system; Replaces a 2-30 damaged nucleotides
Excinuclease protein: excises the incorrect nucleotide and surrounding nucleotides (subunits: UvrA, B, and C)
DNA polymerase I: repairs the gap.
DNA ligase: conducts nick repair. |
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Term
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Definition
Repairs mismatches left by DNA PolIII. Dam methylase adds methyl groups to the A of all (5’)GATC consensus sequences shortly after DNA synthesis.
MutS, L, H, DNA bend.
Helicase II and MutHSL “melt” the dsDNA and the liberated strand is digested by an exconuclease.
DNA PolIII repairs the gap. |
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Term
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Definition
RecA is activated → LexA cleaved and is released from operators…
DNA SOS box controlled repair genes are de-repressed.
CELL CYCLE ARRESTS
•Recombination ramps up to fix double stranded DNA breaks.
•Nucleotide excision repair springs into action (uvr system).
•Error-prone recombinational repair enzymes spring into action (umuC and umuD), especially when repairing pyrimidine dimers |
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