Gindullis F, Meier I
DuPont Central Research and Development, P.O. Box 80402, Wilmington, Delaware 19880-0402, USA.
Plant Cell. 1999 Jun;11(6):1117-28. doi: 10.1105/tpc.11.6.1117.
Recently, it has been suggested that nuclear processes, such as replication, transcription, and splicing, are spatially organized and associated with a nuclear framework called the nuclear matrix, a structure of unknown molecular composition. It has been shown that chromatin is attached to the nuclear matrix via specific DNA fragments called matrix attachment regions (MARs). We have begun to dissect the plant nuclear matrix by isolating a DNA binding protein with specific affinity for MARs. Here, it is shown that MAR binding filament-like protein 1 (MFP1) is associated with specklelike structures at the nuclear periphery that are part of isolated nuclei and the nuclear matrix. A predicted N-terminal transmembrane domain is necessary for the specific targeting of MFP1 to the speckles, indicating an association with the nuclear envelope-endoplasmic reticulum continuum. In addition, it is shown that a marker protein for plant microtubule organizing centers, which has been shown to be localized on the outside of the plant nuclear envelope, is also part of the nuclear matrix. These findings indicate a close and previously undescribed connection in plants between the nuclear envelope and the internal nuclear matrix, and they suggest a function for MFP1 in attaching chromatin to specific sites at the nuclear periphery.
最近，有人提出，诸如复制、转录和剪接等核过程在空间上是有组织的，并与一种称为核基质的核框架相关联，核基质是一种分子组成未知的结构。研究表明，染色质通过称为基质附着区域（MARs）的特定DNA片段附着于核基质。我们已开始通过分离对MARs具有特异性亲和力的DNA结合蛋白来剖析植物核基质。在此，研究表明MAR结合丝状蛋白1（MFP1）与核周边的斑点状结构相关联，这些结构是分离细胞核和核基质的一部分。预测的N端跨膜结构域是MFP1特异性靶向斑点所必需的，这表明其与核膜 - 内质网连续体相关。此外，研究表明，一种已被证明定位于植物核膜外侧的植物微管组织中心标记蛋白也是核基质的一部分。这些发现表明，在植物中核膜与内部核基质之间存在密切且此前未被描述的联系，并且它们暗示了MFP1在将染色质附着于核周边特定位点方面的功能。
