BRCA2の同類であるBrh2は,dsDNA-ssDNAの交差点にあるRAD51のフィラメント形成を核化する

Haijuan Yang¹, Qiubai Li, Jie Fan

¹Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

Nature

|February 11, 2005

まとめ

BRCA2腫瘍抑制タンパク質は,RAD51が重要なフィラメントを形成するのを助けることによってDNA修復を促進します. この研究は,BRCA2を明確にしています.

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
がん研究がん研究

背景:

BRCA2は,同類再結合によるDNA二重鎖破裂 (DSB) 修復に不可欠な腫瘍抑制剤である.
RAD51は,単一鎖DNA (ssDNA) に核タンパク質フィラメントを形成することによって,DSB修復を媒介する.
RAD51媒介による修復におけるBRCA2の正確な役割は,ドメイン効果の相反により,以前は不明でした.

研究の目的:

RAD51媒介の同型再結合におけるBRCA2の機能を明らかにする.
BRCA2がRAD51核タンパク質フィラメントの形成と機能をどのように促進するのかを明らかにする.

主な方法:

リコンビネーションアッセイにおける全長BRCA2ホモログ (Brh2) の機能を調査した.
RAD51フィラメントの核形成と延長に Brh2 の影響を評価した.
Brh2のDNA構造,特にssDNA/dsDNA結合への結合特性を調べました.

主要な成果:

Brh2は,Rad51媒介による再結合を,サブサイキオメトリック濃度で刺激する.
Brh2はRad51をDNAに積極的に採用し,繊維の核形成を促進する.
Brh2は,切断されたDSB交差点の3'オーバーハングに対して厳格な特異性を示しています.

結論:

BRCA2の機能は,3' ssDNAオーバーハングのRAD51フィラメント形成を勧誘し,促進する.
このメカニズムは,正確な同類再結合とエラーのないDSB修復に不可欠です.
機能不全のBRCA2は,BRCA2関連がんにおけるDNA修復能力の喪失を説明する.

さらに関連する動画

07:55

Visualization of DNA Repair Proteins Interaction by Immunofluorescence

Published on: June 26, 2020

06:44

Assessment of Global DNA Double-Strand End Resection using BrdU-DNA Labeling coupled with Cell Cycle Discrimination Imaging

Published on: April 28, 2021

関連する概念動画

02:04

Fixing Double-strand Breaks

The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...

02:31

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...

02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...

02:04

Fixing Double-strand Breaks

02:31

Homologous Recombination

01:18

Other Unique Bacteria

Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic and are commonly found near the...

関連する実験動画