Ikeda Risa, Sakagami Tosuke, Hamada Mayuko, Sakamoto Tatsuya, Hatabu Toshimitsu, Saito Noboru, Ando Motonori
Laboratory of Cell Physiology, Department of Science Education, Faculty of Education, Okayama University, Okayama, Japan.
Laboratory of Animal Physiology and Pharmacology, Department of Animal Science, Faculty of Environmental and Life Science, Okayama University, Okayama, Japan.
J Eukaryot Microbiol. 2023 Mar;70(2):e12955. doi: 10.1111/jeu.12955. Epub 2022 Dec 7.
The centrohelid heliozoan Raphidocystis contractilis has many radiating axopodia, each containing axopodial microtubules. The axopodia show rapid contraction at nearly a video rate (30 frames per second) in response to mechanical stimuli. The axopodial contraction is accompanied by cytoskeletal microtubule depolymerization, but the molecular mechanism of this phenomenon has not been elucidated. In this study, we performed de novo transcriptome sequencing of R. contractilis to identify genes involved in microtubule dynamics such as the rapid axopodial contraction. The transcriptome sequencing generated 7.15-Gbp clean reads in total, which were assembled as 31,771 unigenes. Using the obtained gene sets, we identified several microtubule-severing proteins which might be involved in the rapid axopodial contraction, and kinesin-like genes that occur in gene duplication. On the other hand, some genes for microtubule motor proteins involved in the formation and motility of flagella were not found in R. contractilis, suggesting that the gene repertoire of R. contractilis reflected the morphological features of nonflagellated protists. Our transcriptome analysis provides basic information for the analysis of the molecular mechanism underlying microtubule dynamics in R. contractilis.
中心太阳虫纲的收缩放射太阳虫（Raphidocystis contractilis）有许多放射状的轴足，每个轴足都含有轴足微管。轴足在受到机械刺激时，会以接近视频帧率（每秒30帧）的速度快速收缩。轴足收缩伴随着细胞骨架微管的解聚，但这种现象的分子机制尚未阐明。在本研究中，我们对收缩放射太阳虫进行了从头转录组测序，以鉴定参与微管动态变化（如轴足快速收缩）的基因。转录组测序共产生了7.15 Gbp的clean reads，组装成31,771个单基因。利用获得的基因集，我们鉴定了几种可能参与轴足快速收缩的微管切断蛋白，以及发生基因复制的类驱动蛋白基因。另一方面，在收缩放射太阳虫中未发现一些参与鞭毛形成和运动的微管运动蛋白基因，这表明收缩放射太阳虫的基因库反映了无鞭毛原生生物的形态特征。我们的转录组分析为分析收缩放射太阳虫微管动态变化的分子机制提供了基础信息。
