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In vivo and in vitro Studies of Adaptor-clathrin Interaction
Published on: January 26, 2011
単一鎖DNAの進行性AID触媒によるサイトシン脱アミネーションは,ソマティックハイパーミューテーションをシミュレートします
Phuong Pham1, Ronda Bransteitter, John Petruska
1Department of Biological Sciences, Hedco Molecular Biology Laboratories, University of Southern California, University Park, Los Angeles, California 90089-1340, USA.
Nature
|June 24, 2003
まとめ
アクティベーション誘発型シチジンデアミナーゼ (AID) は,単一鎖DNAのサイトシンをウラシルにデアミナーし,特定のWRC配列をターゲットにします. この酵素は,個々のDNA鎖に複数のデアミネーションを実行し,抗体遺伝子変異の重要な特徴を説明します.
科学分野:
- 免疫学 免疫学とは
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- アクティベーション誘発型シチジンデアミナーゼ (AID) は,B細胞の抗体多様化に不可欠である.
- 抗体クラス・スイッチ・リコンビネーションと体性高変異 (SHM) は,AIDを必要とします.
- AIDは,単一鎖DNA (ssDNA) のサイトシン (C) からウラシル (U) へのデアミネーションを触媒化する.
研究 の 目的:
- AIDのインビトロ触媒活性と基板特異性を調査する.
- AID媒介によるDNA除染のメカニズムを解明する.
- in vitroの発見とSHMのin vivoの特徴を相関させるため.
主な方法:
- 純化されたAIDタンパク質を用いたインビトロ生化学測定法.
- CからUへの除染製品のDNA配列の分析.
- ssDNAおよびDNA複合体に対するAID結合親和性の評価.
主要な成果:
- AIDは,ssDNA上の5' WRC配列内のCを優先的にデアミン化する.
- AIDは,個々のDNA鎖に複数のデアミネーションを行うが,鎖間ジャンプは行わない.
- AIDは,トランスクリプトされた鎖よりも,トランスクリプトされていないDNA鎖を15倍も好むことを示しています.
結論:
- AIDの触媒的活性と基質の好みは,in vitroでは,in vivo SHMの重要な特徴を説明する.
- AIDのssDNAへの強い結合は,正電荷によって誘発され,複数のdeaminationsを容易にする.
- AID 脱酸化による鎖の偏好は,SHM.の転写依存性に関連しています.
関連する概念動画
Mismatch Repair
Overview
Mismatch Repair
Overview
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
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...
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...
Spontaneous and Induced Mutations
Spontaneous mutations arise infrequently during DNA replication due to errors in the process. A key factor behind these errors is tautomeric shifts in nitrogenous bases, where bases transition from keto to enol forms or amino to imino forms. This shift can alter base-pairing rules, leading to mutations. Additionally, reactive oxygen species (ROS) arising from aerobic metabolism can damage DNA, resulting in depurination (loss of a purine base) or depyrimidination (loss of a pyrimidine base).

