可转移元素在异色染色素和表观遗传控制中的作用
Zachary Lippman1, Anne-Valérie Gendrel, Michael Black
1Watson School of Biological Sciences and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
Nature
|July 23, 2004
概括
阿拉比多普西斯中的异色素主要由可转移的元素和重复组成,由DDM1.1调节. 小干扰RNAs (siRNAs) 可能引导这个过程,影响基因表达.
科学领域:
- 遗传学 遗传学 是一个
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 分子生物学分子生物学
背景情况:
- heterochromatin,以凝聚的染色体材料为特征,在中间体和端粒附近发现.
- 间歇性异质色素 (结节) 在植物基因组中很常见,特别是玉米,并且具有重复性和迟复制性.
- 在基因表达中异色素的作用,以多虫的位置效应变异为例,表明具有调节功能.
研究的目的:
- 为了研究Arabidopsis.com中异性染色素的组成和调节.
- 探索可转移元素和小干扰RNAs (siRNAs) 在异染色素形成和基因调节中的作用.
- 了解基因的表观遗传调节由可转移的元素和相关的染色体重塑因素.
主要方法:
- 微阵列分析以确定异色序列.
- 对对应于异色彩区域的小干扰RNA (siRNA) 的分析.
- 研究印制基因FWA的表观遗传调节.
主要成果:
- 阿拉比多普西斯的异色染色体由可转移元素和并列重复确定,由染色体重塑ATPase DDM1 (DNA甲基化减少1) 控制.
- 小干扰RNAs (siRNAs) 与这些异色序列相对应,这表明它们在指导DDM1.1中的作用.
- 移植元素可以在基因内或附近插入时表观遗传调节基因,解释DDM1和MET1对印记基因FWA的调节.
结论:
- 阿拉比多普西斯中的异色素主要由可转移的元素和重复组成,由DDM1调节并由siRNAs指导.
- 可转移的元素在表观遗传基因调节中起着重要作用,特别是当它们位于基因促进体附近时.
- 这项研究阐明了构成异色素蛋白的分子机制及其对植物基因表达和发育的影响.
相关概念视频
Position-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.
Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
DNA-only Transposons
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Transposons
Transposons, or "jumping genes," are small mobile genetic elements (MGEs) that range from 700 to 40,000 base pairs in length. They are found in all organisms and can move within the same chromosome or transfer to different chromosomes. In some cases, transposons can also jump between different host DNA molecules, such as plasmids or viruses, contributing to genetic variability.Barbara McClintock first discovered these mobile genetic elements in the 1940s while studying maize genetics, and she...


