Terasawa Kimihiro, Sato Naoki
Department of Molecular Biology, Faculty of Science, Saitama University, Sakura-ku, Saitama, 338-8570, Japan.
J Plant Res. 2005 Apr;118(2):111-9. doi: 10.1007/s10265-005-0200-z. Epub 2005 Apr 16.
The PEND protein is a DNA-binding protein in the inner envelope membrane of the developing chloroplast. It consists of a short pre-sequence, an N-terminal DNA-binding domain (cbZIP), a central repeat domain, and a C-terminal transmembrane domain. PEND homologs have been detected in various angiosperms, including Arabidopsis thaliana, Brassica napus, Medicago truncatula, cucumber and cherry. Monocot homologs have also been detected in barley and rice, but sequence conservation was low in monocots. PEND-related sequences have not been detected in non-flowering plants and algae. Green fluorescent protein fusions consisting of the N-terminal as well as full-length PEND homologs in A. thaliana and B. napus were targeted to chloroplasts, and localized to nucleoids and chloroplast periphery, respectively. Immunoblot analysis suggested that crucifer homologs were present in chloroplasts probably as a dimer, as in the case of pea. These results suggest that PEND protein is present in angiosperms, and the homologs in crucifers are functionally analogous to the PEND protein in pea.
PEND蛋白是发育中的叶绿体内膜中的一种DNA结合蛋白。它由一个短的前序列、一个N端DNA结合结构域（cbZIP）、一个中央重复结构域和一个C端跨膜结构域组成。在包括拟南芥、甘蓝型油菜、蒺藜苜蓿、黄瓜和樱桃在内的各种被子植物中都检测到了PEND同源物。在大麦和水稻中也检测到了单子叶植物同源物，但单子叶植物中的序列保守性较低。在非开花植物和藻类中未检测到与PEND相关的序列。由拟南芥和甘蓝型油菜的N端以及全长PEND同源物组成的绿色荧光蛋白融合体靶向叶绿体，分别定位于类核和叶绿体周边。免疫印迹分析表明，十字花科同源物可能以二聚体形式存在于叶绿体中，就像豌豆中的情况一样。这些结果表明，PEND蛋白存在于被子植物中，十字花科中的同源物在功能上与豌豆中的PEND蛋白类似。
