逆转移子扩张的波浪在多种哺乳动物系中重塑了基因组组织和CTCF结合
Dominic Schmidt1, Petra C Schwalie, Michael D Wilson
1Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.
Cell
|January 17, 2012
概括
这项研究在哺乳动物中确定了保存的CTCF结合点,揭示了古代的反元素推动了这些调节性DNA元素的传播,塑造了基因组的进化.
科学领域:
- 基因组学就是基因组学.
- 进化生物学 进化生物学
- 分子生物学分子生物学
背景情况:
- 结合CTCF的位置是关键的调节性DNA元素,在进化过程中受到限制.
- 了解它们的保护和基因组传播是解读基因组演变的关键.
研究的目的:
- 定义CTCF绑定站点的全部范围,包括一个特定的图案.
- 在多种哺乳动物物种中确定保存的CTCF结合位置.
- 调查CTCF绑定在扩展和演变中的反向元件的作用.
主要方法:
- 对六种哺乳动物物种的ChIP-seq数据进行比较分析.
- 使用强大的图案识别保存的CTCF结合点.
- 生物信息分析用于检测与CTCF站点相关的重复元素.
主要成果:
- 确定了超过五千个高度保存,坚固和组织独立的CTCF结合位置.
- 研究人员发现,逆元件的激活会导致动物,狗和鱼中CTCF结合的特定物种扩展.
- 这些扩展的CTCF结合部位通常作为染色质和转录绝缘体起作用.
- 化石重复元素被发现围绕着深度保存的CTCF结合区域,表明古代的逆转移子活动.
结论:
- 重复驱动的分散是哺乳动物基因组进化的基本,古老和活跃的机制.
- 在整个哺乳动物进化过程中,逆转移素活性塑造了CTCF结合部位的分布和功能.
- 在维护基因组结构和通过进化时间调节基因表达方面,CTCF结合部位起着至关重要的作用.
相关概念视频
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...
LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
Non-LTR Retrotransposons
As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
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...


