相关实验视频

Updated: Jul 23, 2025

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy

Published on: June 25, 2013

RecA的高度不匹配耐受性同质测试可以解释同质长度如何影响重组

Mara Prentiss¹, Dianzhuo Wang¹, Jonathan Fu¹

¹Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America.

|July 13, 2023

概括

RecA蛋白通过寻找同源序列来促进DNA修复. 这项研究表明,ReCA可以形成高达16%不匹配的重组产品,挑战了以前关于DNA同质测试严格性的假设.

科学领域:

分子生物学分子生物学
遗传学是一个遗传学.
生物物理学的生物物理.

背景情况:

双链断裂 (DSB) 触发了涉及ReCA蛋白的DNA修复途径.
RecA通过同类搜索来识别维修模板.
现有的模型表明,RecA应该拒绝不匹配的重组产品,但仍观察到不匹配.

研究的目的:

为了研究ReCA介导的同类测试在体外的不匹配耐受性.
评估同类测试严格性的理论模型,具有不同的不匹配容忍度和序列长度 (Ltest).
将模型预测与细菌基因组特征和体内重组要求进行比较.

主要方法:

在体外实验中,形成ReCA介导的重组产品,具有受控的不匹配百分比.
开发和应用对同质性测试严格性的理论模型.
使用随机生成和细菌基因组分析模型.

主要成果:

在实验室中,ReCA形成可观测的重组产物,在实验室中高达16%的不匹配.
对于随机基因组,严格性随着不匹配耐受性而下降,随着Ltest.增加.
对于细菌基因组,由于重复序列,75bp的Ltest可以达到99%的严格性,而不考虑不匹配的耐受性.

结论:

细菌基因组在同类测试中具有显著的不匹配耐受性 (~75bp).
延长LTest超出75bp的时间,对细菌基因组没有显著的改善.
在体内重组的承诺与~75bp的同类测试一致,表明高不匹配不耐受性.

更多相关视频

Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae

Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae

Published on: September 11, 2022

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51

Published on: February 13, 2019

相关概念视频

Homologous Recombination

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...

Crossing Over

Crossing Over

Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I,...

Mismatch Repair

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...

Conservative Site-specific Recombination and Phase Variation

Conservative Site-specific Recombination and Phase Variation

Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...

Gene Conversion

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...

Fixing Double-strand Breaks

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...