Structure and function of plastid nucleoid

质体类核是质体DNA的一个功能单位，被认为是原核生物DNA与真核生物DNA结合蛋白的复合物或杂交体。基于这一观点，我们试图鉴定质体类核的组分，并分析它们在质体DNA复制和转录中的功能。拟南芥基因组全序列的公布使我们得出结论，许多原核生物的类核蛋白在高等植物中并不存在。实例是普遍存在于原核生物中的HU蛋白和Dps蛋白，但它们不存在于A.许多类核蛋白必须在陆生植物进化过程中通过编码真核DNA结合蛋白的核基因的复制或修饰获得。这些结果促使我们提出了一个假说的不连续进化的质体基因组机器。

Plastid nucleoid, which is a functional unit of plastid DNA, is considered as a complex or hybrid of prokaryotic DNA with eukaryotic DNA-binding proteins. Based on this standpoint, we tried to identify the components of plastid nucleoids and to analyze their function in the replication and transcription of plastid DNA. The publication of the complete nucleotide sequence of the genome of Arabidopsis thaliana made us conclude that many of the prokaryotic nucleoid proteins are not present in higher plants. Examples are the HU protein and Dps protein that are ubiquitously present in prokaryotes but these are not present in the chloroplast of A. thaliana.Many of the nucleoid proteins must have been acquired during the evolution of land plants by duplication or modification of the nuclear genes encoding eukaryotic DNA-binding proteins. These results prompted us to put forward a hypothesis on the discontinuous evolution of plastid genomic machinery.