CENTRIPETAL FLOW AND DIRECTED REASSEMBLY OF THE MAJOR SPERM PROTEIN (MSP) CYTOSKELETON IN THE AMEBOID SPERM OF THE NEMATODE, ASCARIS-SUUM
CENTRIPETAL FLOW AND DIRECTED REASSEMBLY OF THE MAJOR SPERM PROTEIN (MSP) CYTOSKELETON IN THE AMEBOID SPERM OF THE NEMATODE, ASCARIS-SUUM
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DOI：
10.1002/cm.970200306
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发表时间：
1991-01-01
影响因子：
--
通讯作者：
KING, KL
中科院分区：
文献类型：
--
作者：
ROBERTS, TM;KING, KL
猪蛔虫变形体精子的细胞骨架由主要的精子蛋白(MSP)细丝组成，这些细丝排列成长的分支纤维复合体，由于复合体的相对端的组装和拆卸，这些复合体向后连续地跨越伪足和跑步机的长度(Sepsenwol等，Journal of Cell Biology 108：55-66，(1989))。视频增强显微镜检查表明，这种细胞骨架流动与精子运动紧密相连。纤维复合体以与细胞向前爬行相同的速度(10-50微米/分钟)向后爬行。只有质膜末端在伪足前缘的有限扇区内的纤维复合体进行了连续组装。因此，这个约占伪足周长50%的扇区的位置决定了精子运动的方向。用弱酸和原生团等降低细胞内pH值的试剂处理精子，会导致纤维复合体在4-5秒内完全解体。这些化合物的去除导致了细胞骨架的重新组装，其模式类似于完整精子的踏板磨削。纤维复合体在其质膜末端通过组装而重建，从而在30-60秒内整个细丝系统重建，细胞恢复运动。细胞骨架重组和跑步机都需要外源HCO3-。这些结果表明，细胞内pH的变化可能有助于调节细胞骨架的踏车，从而在精子运动中发挥重要作用。
The cytoskeleton of the amoeboid spermatozoa of Ascaris suum consists of major sperm protein (MSP) filaments arranged into long, branched fiber complexes that span the length of the pseudopod and treadmill rearward continuously due to assembly and disassembly at opposite ends of the complexes (Sepsenwol et al., Journal of Cell Biology 108:55-66, (1989)). Examination by video-enhanced microscopy showed that this cytoskeletal flow is tightly coupled to sperm locomotion. The fiber complexes treadmilled rearward at the same rate (10-50-mu-m/min) as the cell crawled forward. Only fiber complexes with their plasmalemmal ends within a limited sector along the leading edge of the pseudopod underwent continuous assembly. Thus, the location of this sector, which occupies about 50% of the pseudopod perimeter, determined the direction of sperm locomotion. Treatment of sperm with agents that lower intracellular pH, such as weak acids and protonophores, caused the fiber complexes to disassemble completely in 4-5 sec. Removal of these compounds resulted in reassembly of the cytoskeleton in a pattern that mimicked treadmilling in intact sperm. The fiber complexes were reconstructed by assembly at their plasmalemmal ends so that within 30-60 sec the entire filament system reformed and the cell resumed locomotion. Both cytoskeletal reassembly and treadmilling required exogenous HCO3-. These results suggest that variation in intracellular pH may help regulate cytoskeletal treadmilling and thereby play a significant role in sperm locomotion.