ヘテロデュプレックス補正がSaccharomyces cerevisiaeにおける遺伝子変換における役割
Nature
|July 23, 1987
まとめ
酵母におけるメオティック遺伝子変換には,DNA不一致の修正が含まれています. pms1の変異は,このプロセスを妨害し,メオシス中に変異したアレル分離周波数につながります.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- イースト遺伝学 イースト遺伝学
背景:
- 菌類における非メンデルのアレル分離は,ヘテロデュプレックス補正または二重鎖のギャップ修復という2つのモデルによって説明されます.
- これらのモデルは,不一致補正の結果に基づいて,異なるテトラド周波数 (例えば6:2と5:3タイプ) を予測します.
研究 の 目的:
- 中間遺伝子変換における不一致補正の役割を調査する.
- Saccharomyces cerevisiaeのヘテロデュプレックスDNA補正とテトラド分離周波数に対するpms1変異の影響を分析する.
主な方法:
- Saccharomyces cerevisiaeのpms1変異株におけるヘテロデュプレックスプラズミドDNA補正を研究した.
- 変異型と野生型株におけるテトラド分離周波数 (5:3 と 6:2 タイプ) の比較.
主要な成果:
- pms1変異株は,野生型と比較して 5:3テトラドのより高い周波数と 6:2テトラドのより低い周波数を示した.
- これらの結果は,pms1変異体内の不一致補正の欠陥を示しています.
結論:
- pms1変異は,微生物分裂中のDNA不一致修復を損なう.
- 野生型酵母におけるメイオティック遺伝子変換は,ヘテロデュプレックスDNAの修正を含む可能性が高い.
関連する概念動画
Mismatch Repair
Overview
Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
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DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a long stretch of wrong bases may get added to the daughter strands. If the errors are left unchecked, cells might accumulate several mutations that might endanger their survival. Therefore, the copying errors are checked and repaired at three levels.
Mismatch Repair
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...


