Sumiya Nobuko, Miyagishima Shin-Ya
Department of Cell Genetics, National Institute of Genetics, Shizuoka, Japan.
Core Research for Evolutional Science and Technology Program, Japan Science and Technology Agency, Saitama, Japan.
Commun Integr Biol. 2017 Feb 17;10(2):e1294298. doi: 10.1080/19420889.2017.1294298. eCollection 2017.
Chloroplasts have evolved from a cyanobacterial endosymbiont and multiply by dividing. Chloroplast division is performed by constriction of the ring-like protein complex (the PD machinery), which forms at the division site. The PD machinery is composed of cyanobacteria-descended components such as FtsZ and eukaryote-derived proteins such as the dynamin-related protein, DRP5B. In the red alga , FtsZ ring formation on the stromal side precedes PDR1 and DRP5B ring formation on the cytosolic side. In this study, we impaired FtsZ ring formation in by overexpressing FtsZ just before FtsZ ring formation. As a result, PDR1 and DRP5B failed to localize at the chloroplast division site, suggesting that FtsZ ring formation is required for the PDR1 and DRP5B rings. We further found, by expressing a dominant negative form of DRP5B, that DRP5B ring formation begins on the nuclear side of the chloroplast division site. These findings provide insight into how the PD machinery forms in red algae.
叶绿体由蓝藻内共生体进化而来，并通过分裂进行增殖。叶绿体分裂是由在分裂位点形成的环状蛋白质复合物（PD机制）的收缩来完成的。PD机制由源自蓝藻的成分（如FtsZ）和真核生物衍生的蛋白质（如动力蛋白相关蛋白DRP5B）组成。在红藻中，基质侧的FtsZ环形成先于胞质侧的PDR1和DRP5B环形成。在本研究中，我们通过在FtsZ环形成之前过量表达FtsZ来破坏其在红藻中的环形成。结果，PDR1和DRP5B未能定位在叶绿体分裂位点，这表明FtsZ环形成是PDR1和DRP5B环所必需的。我们通过表达DRP5B的显性负性形式进一步发现，DRP5B环形成始于叶绿体分裂位点的核侧。这些发现为红藻中PD机制的形成方式提供了见解。
