Ushimaru Yuji, Konno Aru, Kaizu Maiko, Ogawa Kazuo, Satoh Nori, Inaba Kazuo
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
Zoolog Sci. 2006 Aug;23(8):679-87. doi: 10.2108/zsj.23.679.
We previously identified a 66 kDa axonemal protein (Ci-Axp66.0) in sperm of the ascidian Ciona intestinalis. Here we found that Ci-Axp66.0 shows sequence similarity to the DC2 subunit of the Chlamydomonas outer arm docking complex. Analysis of secondary structure of Ci-Axp66.0 suggested that the N-terminal two-thirds of the molecule is rich in coiled coil structure, as in Chlamydomonas DC2. Immunogold localization revealed that it is located in the vicinity of outer arm dynein. Ci-Axp66.0 was partly extracted from the axonemes by a high salt solution and co-purified with outer arm dynein. This co-purification was not affected by the absence of Mg(2+) in isolation buffer, indicating that Ci-Axp66.0 is associated with outer arm dynein. These results suggest that Ci-Axp66.0 is a component of the outer arm dynein docking complex in the axonemes of Ciona sperm.
我们之前在海鞘玻璃海鞘的精子中鉴定出一种66 kDa的轴丝蛋白（Ci-Axp66.0）。在此，我们发现Ci-Axp66.0与衣藻外臂对接复合体的DC2亚基具有序列相似性。对Ci-Axp66.0二级结构的分析表明，该分子的N端三分之二富含卷曲螺旋结构，与衣藻DC2相同。免疫金定位显示它位于外臂动力蛋白附近。Ci-Axp66.0可被高盐溶液从轴丝中部分提取出来，并与外臂动力蛋白共纯化。这种共纯化不受分离缓冲液中Mg(2+)缺失的影响，表明Ci-Axp66.0与外臂动力蛋白相关。这些结果表明，Ci-Axp66.0是玻璃海鞘精子轴丝中外臂动力蛋白对接复合体的一个组成部分。
