Preparing to move: assembly of the MSP amoeboid motility apparatus during spermiogenesis in Ascaris.
Preparing to move: assembly of the MSP amoeboid motility apparatus during spermiogenesis in Ascaris.
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准备移动：蛔虫精子发生过程中 MSP 变形虫运动装置的组装。
DOI：
10.1002/cm.20058
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Roberts,ThomasM
中科院分区：
文献类型：
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作者：
Rodriguez,MariaAntonia;LeClaire3rd,LawrenceL;Roberts,ThomasM
我们利用非活动蛔虫快速诱导转化为爬行精子来检查为精子运动提供动力的 MSP 运动装置的组装模式。在活精子中，第一个可检测到的运动活动是尖峰的延伸，随后是细胞表面的气泡的延伸。然而，通过电镜检查细胞发现，在表面突起形成之前，MSP 丝尾在外周细胞质的膜细胞器上组装。这些与细胞器相关的丝状网络在诱导精子发生后 30 秒内组装，并持续存在，直到板状足延伸时膜细胞器被隔离到细胞体内。丝状伪足状的尖峰充满了成束的细丝，可以快速伸展和缩回，但只持续几秒钟，然后就会让位于或转化为气泡。这些气泡的聚结，每个气泡都由致密的丝网支撑，通常会引发片状足的延伸，最终形成坚固、动态的 MSP 纤维复合物，从而产生精子的活力。在精子发生过程中，在所有细丝组装位点也发现了在成熟精子的板状足前缘协调纤维复合物组装的相同膜磷蛋白。构建功能性运动装置的有序步骤说明了发育细胞中 MSP 丝组装的精确时空控制，并强调了传统爬行细胞中 MSP 细胞骨架和肌动蛋白丝阵列在组织和可塑性方面的显着相似性。细胞动力。细胞骨架 60:191–199, 2005 © 2005 Wiley‐Liss, Inc.
We exploited the rapid, inducible conversion of non‐motileAscarisspermatids into crawling spermatozoa to examine the pattern of assembly of the MSP motility apparatus that powers sperm locomotion. In live sperm, the first detectable motile activity is the extension of spikes and, later, blebs from the cell surface. However, examination of cells by EM revealed that the formation of surface protrusions is preceded by assembly of MSP filament tails on the membranous organelles in the peripheral cytoplasm. These organelle‐associated filament meshworks assemble within 30 sec after induction of spermiogenesis and persist until the membranous organelles are sequestered into the cell body when the lamellipod extends. The filopodia‐like spikes, which are packed with bundles of filaments, extend and retract rapidly but last only a few seconds before giving way to, or converting into, blebs. Coalescence of these blebs, each supported by a dense mesh of filaments, often initiates lamellipod extension, which culminates in the formation of the robust, dynamic MSP fiber complexes that generate sperm motility. The same membrane phosphoprotein that orchestrates assembly of the fiber complexes at the leading edge of the lamellipod of mature sperm is also found at all sites of filament assembly during spermiogenesis. The orderly progression of steps that leads to construction of a functional motility apparatus illustrates the precise spatio‐temporal control of MSP filament assembly in the developing cell and highlights the remarkable similarity in organization and plasticity shared by the MSP cytoskeleton and the actin filament arrays in conventional crawling cells. Cell Motil. Cytoskeleton 60:191–199, 2005 © 2005 Wiley‐Liss, Inc.