Basiri Marcus L, Ha Andrew, Chadha Abhishek, Clark Nicole M, Polyanovsky Andrey, Cook Boaz, Avidor-Reiss Tomer
Department of Biological Sciences, University of Toledo, 3050 W. Towerview Boulevard, Toledo, OH 43606, USA.
Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Curr Biol. 2014 Nov 17;24(22):2622-31. doi: 10.1016/j.cub.2014.09.047. Epub 2014 Oct 30.
In most cells, the cilium is formed within a compartment separated from the cytoplasm. Entry into the ciliary compartment is regulated by a specialized gate located at the base of the cilium in a region known as the transition zone. The transition zone is closely associated with multiple structures of the ciliary base, including the centriole, axoneme, and ciliary membrane. However, the contribution of these structures to the ciliary gate remains unclear.
Here we report that, in Drosophila spermatids, a conserved module of transition zone proteins mutated in Meckel-Gruber syndrome (MKS), including Cep290, Mks1, B9d1, and B9d2, comprise a ciliary gate that continuously migrates away from the centriole to compartmentalize the growing axoneme tip. We show that Cep290 is essential for transition zone composition, compartmentalization of the axoneme tip, and axoneme integrity and find that MKS proteins also delimit a centriole-independent compartment in mouse spermatids.
Our findings demonstrate that the ciliary gate can migrate away from the base of the cilium, thereby functioning independently of the centriole and of a static interaction with the axoneme to compartmentalize the site of axoneme assembly.
在大多数细胞中，纤毛在与细胞质分隔的一个区室中形成。进入纤毛区室受位于纤毛基部一个称为过渡区的区域中的一个特殊门控调节。过渡区与纤毛基部的多种结构密切相关，包括中心粒、轴丝和纤毛膜。然而，这些结构对纤毛门控的贡献仍不清楚。
在此我们报告，在果蝇精子细胞中，在梅克尔-格鲁伯综合征（MKS）中发生突变的一个保守的过渡区蛋白模块，包括Cep290、Mks1、B9d1和B9d2，构成一个纤毛门控，该门控不断从中心粒迁移以分隔生长中的轴丝顶端。我们表明Cep290对于过渡区组成、轴丝顶端的分隔以及轴丝完整性至关重要，并发现MKS蛋白在小鼠精子细胞中也界定了一个不依赖于中心粒的区室。
我们的发现表明，纤毛门控可以从纤毛基部迁移开，从而独立于中心粒以及与轴丝的静态相互作用发挥作用，以分隔轴丝组装位点。
