Jeong Sun Yong, Rose Annkatrin, Meier Iris
Department of Plant Biology and Plant Biotechnology Center, Ohio State University, 244 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210, USA.
Nucleic Acids Res. 2003 Sep 1;31(17):5175-85. doi: 10.1093/nar/gkg693.
Plastid DNA, like bacterial and mitochondrial DNA, is organized into protein-DNA complexes called nucleoids. Plastid nucleoids are believed to be associated with the inner envelope in developing plastids and the thylakoid membranes in mature chloroplasts, but the mechanism for this re-localization is unknown. Here, we present the further characterization of the coiled-coil DNA-binding protein MFP1 as a protein associated with nucleoids and with the thylakoid membranes in mature chloroplasts. MFP1 is located in plastids in both suspension culture cells and leaves and is attached to the thylakoid membranes with its C-terminal DNA-binding domain oriented towards the stroma. It has a major DNA-binding activity in mature Arabidopsis chloroplasts and binds to all tested chloroplast DNA fragments without detectable sequence specificity. Its expression is tightly correlated with the accumulation of thylakoid membranes. Importantly, it is associated in vivo with nucleoids, suggesting a function for MFP1 at the interface between chloroplast nucleoids and the developing thylakoid membrane system.
质体DNA与细菌和线粒体DNA一样，被组织成称为类核的蛋白质-DNA复合物。质体类核被认为在发育中的质体中与内膜相关，在成熟叶绿体中与类囊体膜相关，但这种重新定位的机制尚不清楚。在这里，我们进一步表征了卷曲螺旋DNA结合蛋白MFP1，它是一种与成熟叶绿体中的类核和类囊体膜相关的蛋白质。MFP1存在于悬浮培养细胞和叶片的质体中，其C末端DNA结合结构域朝向基质附着在类囊体膜上。它在成熟拟南芥叶绿体中具有主要的DNA结合活性，并且能结合所有测试的叶绿体DNA片段，没有可检测到的序列特异性。其表达与类囊体膜的积累紧密相关。重要的是，它在体内与类核相关，表明MFP1在叶绿体类核与发育中的类囊体膜系统之间的界面处发挥作用。
