The germ line limited M element of Tetrahymena is targeted for elimination from the somatic genome by a homology-dependent mechanism.
The germ line limited M element of Tetrahymena is targeted for elimination from the somatic genome by a homology-dependent mechanism.
复制标题
DOI：
10.1093/nar/gkl699
复制
发表时间：
2006
影响因子：
14.9
通讯作者：
Chalker DL
中科院分区：
文献类型：
--
作者：
Kowalczyk CA;Anderson AM;Arce-Larreta M;Chalker DL
类似RNA干扰（RNAi）的机制涉及从四膜虫发育中的体细胞大核中消除数千个DNA片段，但如何识别特定的内部消除序列（IES）仍有待充分阐明。为了确定 DNA 重排的要求，我们对 M 元件（一种经过充分研究的 IES）进行了诱变。虽然已知大核保留 DNA 内的序列决定切除边界，但我们表明这些边界内部的序列需要促进 IES 重排。然而，该元件不包含顺式所需的任何特定序列，因为去除其整个左侧或右侧不足以消除所有重排。相反，重排效率与给定构建体中 M 元件序列的整体大小相关，下限接近 300 bp。此外，观察到的表观遗传阻断切除所需的最小区域支持这一大小限制。表现出重排受损的截短 M 元件构建体仍然表现出完整的转录活性，这表明它们的缺陷是由于识别效率低下造成的。这项研究表明 IES 在被同源小 RNA 识别后就成为消除的目标，并进一步支持了 DNA 消除是参与基因组监视的 RNAi 相关机制的观点。
A RNA interference (RNAi) like mechanism is involved in elimination of thousands of DNA segments from the developing somatic macronucleus of Tetrahymena, yet how specific internal eliminated sequences (IESs) are recognized remains to be fully elucidated. To define requirements for DNA rearrangement, we performed mutagenesis of the M element, a well-studied IES. While sequences within the macronucleus-retained DNA are known to determine the excision boundaries, we show that sequences internal to these boundaries are required to promote this IES's rearrangement. However, this element does not contain any specific sequence required in cis as removal of its entire left or right side was insufficient to abolish all rearrangement. Instead, rearrangement efficiency correlated with the overall size of the M element sequence within a given construct, with a lower limit of nearly 300 bp. Also, the observed minimal region necessary to epigenetically block excision supports this size limit. Truncated M element constructs that exhibited impaired rearrangement still showed full transcriptional activity, which suggests that their defect was due to inefficient recognition. This study indicates that IESs are targeted for elimination upon their recognition by homologous small RNAs and further supports the idea that DNA elimination is a RNAi-related mechanism involved in genome surveillance.
登录
查看更多内容
影响因子：
10.5
作者：
Chalker, DL;Yao, MC
通讯作者：
Yao, MC
影响因子：
10.5
作者：
GODISKA, R;JAMES, C;YAO, MC
通讯作者：
YAO, MC
影响因子：
--
作者：
Liu, YF;Song, XY;Karrer, KM
通讯作者：
Karrer, KM
影响因子：
5.3
作者：
Duharcourt, S;Keller, AM;Meyer, E
通讯作者：
Meyer, E
影响因子：
3.7
作者：
MARTINDALE, DW;ALLIS, CD;BRUNS, PJ
通讯作者：
BRUNS, PJ