通过素H3氨酸27甲基转移酶调节异色染色DNA复制
Yannick Jacob1, Hume Stroud, Chantal Leblanc
1Department of Biology, Indiana University, 915 East Third Street, Bloomington, Indiana 47405, USA.
Nature
|July 16, 2010
概括
激素修饰剂ARABIDOPSIS TRITHORAX-RELATED PROTEIN5 (ATXR5) 和ATXR6中的突变导致Arabidopsis中的DNA重复复制. 这项研究揭示了一种新的途径,可以防止异色染色素过度复制,并影响转子子表达.
科学领域:
- 分子生物学分子生物学
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 植物科学 植物科学
背景情况:
- 细胞周期调节可以防止DNA在每个细胞周期中复制一次以上.
- 基因组起源的复制前复合体是控制DNA复制的关键目标.
- 基因组修饰在调节基因表达和基因组稳定性方面发挥着至关重要的作用.
研究的目的:
- 为了研究基因组3氨酸27 (H3K27) 单甲基转移酶ATXR5和ATXR6在防止DNA重复制中的作用.
- 为了确定基因组区域容易在ATXR5和ATXR6.6突变后重复复制.
- 了解ATXR5和ATXR6突变对转体子表达和植物发育的影响.
主要方法:
- 对缺乏功能ATXR5和ATXR6.6的阿拉比多普西斯突变物进行遗传分析.
- 全基因组分析以确定DNA重复复制的部位.
- 在特定的基因组位置分析H3K27单甲基化水平.
- 转子子体的基因表达分析.
- 植物发育的表型分析.
主要成果:
- 在ATXR5和ATXR6中发生的突变导致Arabidopsis中特定基因组位置的重复复制.
- 重复复制的区域主要与转位子和其他重复的静音基因组元素相对应.
- 在这些重复复制的部位观察到高水平的H3K27单甲基化.
- 催化SET域ATXR5/ATXR6的突变足以导致重复复制缺陷.
- ATXR5和ATXR6突变导致转体子表达的上调和发育异常.
结论:
- ATXR5和ATXR6在一种新的途径中起作用,以防止Arabidopsis中异性染色素的DNA过度复制.
- 通过ATXR5/ATXR6进行H3K27单甲基化对于抑制重复复制的重复元素至关重要.
- 这种途径的调节失调会影响基因组稳定性,转子子活性和植物发育.
更多相关视频
相关概念视频
02:32Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
02:31Homologous 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...
02:08Gene 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...
02:53Conservative 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...
The recognition sites for Cre recombinase called LoxP...
02:46Genome Copying Errors
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.
02:08Gene 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...