Dynamics of localization and protein composition of plastid nucleoids in light-grown pea seedlings
Dynamics of localization and protein composition of plastid nucleoids in light-grown pea seedlings
复制标题
光生豌豆幼苗质体核苷的定位和蛋白质组成动态
作者：
N. Sato;O. Misumi;Y. Shinada;M. Sasaki;M. Yoine
摘要分析了豌豆幼苗叶片发育不同阶段叶绿体类核体的定位和蛋白质组成。在未开放的幼叶芽中，类核物质丰富且定位于叶绿体的外围，而在成熟叶片中，叶绿体中的类核物质位于狭小的空间内，受到类囊体或基粒的限制。类核物质在基粒形成之前迁移到质体内部，从而使光合作用器官成熟。幼叶绿体和成熟叶绿体中类核物质的蛋白质组成有很大不同。幼叶绿体的核团中以70-100 kDa的多肽为主，成熟叶绿体的核团中含有大量的20-30 kDa的多肽。免疫印迹分析表明，与成熟叶绿体的类核相比，幼体的类核中的多肽含量要高得多。这些结果表明，在光照下叶绿体的正常发育过程中，类叶绿体的定位和组成都受到动态变化的影响。
SummaryLocalization and protein composition of plastid nucleoids was analyzed in light-grown pea seedlings at various stages of leaf development. In young plastids of unopened leaf buds, nucleoids were abundant and localized in the periphery of plastids, whereas, in mature leaves, chloroplasts contained nucleoids within narrow spaces restricted by thylakoids or grana. The migration of nucleoids into the interior of plastids preceded the formation of grana, and hence, the maturation of the photosynthetic apparatus. The protein composition of nucleoids was considerably different in young plastids and mature chloroplasts. Polypeptides with a molecular mass of 70–100 kDa predominated in the nucleoids of young plastids, whereas polypeptides with molecular mass of 20–30 kDa were abundant in the nucleoids of mature chloroplasts. Immuno-blot analysis with antibodies against the nucleoids of young plastids identified various polypeptides that were significantly more abundant in the nucleoids of young plastids than in the nucleoids of mature chloroplasts. These results demonstrate that plastid nucleoids are subject to dynamic changes in both localization and composition during the normal development of chloroplasts in the light.