Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan.
J Plant Res. 2012 May;125(3):417-28. doi: 10.1007/s10265-011-0444-8. Epub 2011 Jul 14.
Chloroplasts change their positions in a cell in response to light intensities. The photoreceptors involved in chloroplast photo-relocation movements and the behavior of chloroplasts during their migration were identified in our previous studies, but the mechanism of movement has yet to be clarified. In this study, the behavior of actin filaments under various light conditions was observed in Adiantum capillus-veneris gametophytes. In chloroplasts staying in one place under a weak light condition and not moving, circular structures composed of actin filaments were observed around the chloroplast periphery. In contrast, short actin filaments were observed at the leading edge of moving chloroplasts induced by partial cell irradiation. In the dark, the circular structures found under the weak light condition disappeared and then reappeared around the moving chloroplasts. Mutant analyses revealed that the disappearance of the circular actin structure was mediated by the blue light photoreceptor, phototropin2.
叶绿体根据光强改变在细胞中的位置。在我们之前的研究中，确定了参与叶绿体光定位运动的光受体和叶绿体在迁移过程中的行为，但运动的机制尚未阐明。在这项研究中，观察了在凤尾蕨配子体中不同光照条件下肌动蛋白丝的行为。在弱光条件下停留在一个地方不移动的叶绿体中，观察到围绕叶绿体周边的由肌动蛋白丝组成的圆形结构。相比之下，在部分细胞照射诱导下移动的叶绿体前缘观察到短的肌动蛋白丝。在黑暗中，弱光条件下发现的圆形结构消失，然后在移动的叶绿体周围重新出现。突变分析表明，圆形肌动蛋白结构的消失是由蓝光光受体向光素 2 介导的。
