Dynamic nuclear reorganization during genome remodeling of Tetrahymena.
Dynamic nuclear reorganization during genome remodeling of Tetrahymena.
复制标题
DOI：
10.1016/j.bbamcr.2008.07.012
复制
发表时间：
2008-11
期刊：
影响因子：
--
通讯作者：
Chalker DL
中科院分区：
文献类型：
--
作者：
Chalker DL
单细胞纤毛虫嗜热四膜虫（Tetrahymena thermophila）的基因组有两个版本，一个是生殖细胞，一个是体细胞，包含在功能不同的细胞核（分别称为微核和大核）中。这两个基因组从相同的合子拷贝中区分出来。体细胞核的发育涉及大规模的DNA重排，其消除了15至20 Mbp的生殖系衍生DNA。切除的基因组区域分散在整个基因组中，并且主要由重复序列组成。这些种系限制性序列通过RNA干扰（RNAi）相关机制从基因组中去除，该机制将组蛋白H3赖氨酸9和27甲基化引导至其相关的染色质。靶向小RNA在减数分裂期间在微核中产生，然后与亲本大核进行比较，以进一步富集种系限制性序列，并确保仅消除非基因DNA片段。一旦小RNA指导这些染色质修饰，DNA重排机制，包括染色体结构域蛋白Pdd1p和Pdd3p，在这些分散的染色体序列上组装，然后将其分配到发生切除事件的核灶中。这种DNA重排机制相当于四膜虫通过形成异染色质来沉默重复序列。发生的动态核重组提供了一个有趣的一瞥机制，在真核发育过程中形成核结构。
The single-celled ciliate Tetrahymena thermophila possesses two versions of its genome, one germline, one somatic, contained within functionally distinct nuclei (called the micronucleus and macronucleus, respectively). These two genomes differentiate from identical zygotic copies. The development of the somatic nucleus involves large-scale DNA rearrangements that eliminate 15 to 20 Mbp of their germline derived DNA. The genomic regions excised are dispersed throughout the genome and are largely composed of repetitive sequences. These germline-limited sequences are targeted for removal from the genome by a RNA interference (RNAi)-related machinery that directs histone H3 lysine 9 and 27 methylation to their associated chromatin. The targeting small RNAs are generated in the micronucleus during meiosis and then compared against the parental macronucleus to further enrich for germline-limited sequences and ensure that only nongenic DNA segments are eliminated. Once the small RNAs direct these chromatin modifications, the DNA rearrangement machinery, including the chromodomain proteins Pdd1p and Pdd3p, assembles on these dispersed chromosomal sequences, which are then partitioned into nuclear foci where the excision events occur. This DNA rearrangement mechanism is Tetrahymena’s equivalent to the silencing of repetitive sequences by the formation of heterochromatin. The dynamic nuclear reorganization that occurs offers an intriguing glimpse into mechanisms that shape nuclear architecture during eukaryotic development.
登录
查看更多内容
影响因子：
2.7
作者：
HAYASHI, T;HAYASHI, H;IWAI, K
通讯作者：
IWAI, K
DOI：
10.1073/pnas.0509333103
发表时间：
2006-02-21
影响因子：
11.1
作者：
Kotaja, N;Bhattacharyya, SN;Sassone-Corsi, P
通讯作者：
Sassone-Corsi, P
影响因子：
--
作者：
EDDY, EM
通讯作者：
EDDY, EM
DOI：
10.1073/pnas.232688099
发表时间：
2003-01-07
影响因子：
11.1
作者：
Hall, IM;Noma, K;Grewal, SIS
通讯作者：
Grewal, SIS
影响因子：
10.5
作者：
Chalker, DL;Yao, MC
通讯作者：
Yao, MC