The flagellar beat of rat sperm is organized by the interaction of two functionally distinct populations of dynein bridges with a stable central axonemal partition.
The flagellar beat of rat sperm is organized by the interaction of two functionally distinct populations of dynein bridges with a stable central axonemal partition.
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大鼠精子的鞭毛节拍是通过两个功能不同的动力蛋白桥群与稳定的中央轴丝分区的相互作用来组织的。
作者：
C. Lindemann;Angela Orlando;K. Kanous
在大鼠精子鞭毛轴丝中观察到两种不同的微管滑动模式。特定的滑动模式是由用于准备轴丝解体的精子的提取条件决定的。将Triton X-100提取的精子在pH 9.0的浓缩悬浮液中孵育得到的精子，通过挤压双胞体和编号为4至7的外部致密纤维来解体，以响应mg-ATP。将活动的Triton X-100提取模型在37摄氏度下孵育1至3小时制备的精子挤出双胞体和外部致密纤维9、1和2。两种方案解体的轴丝往往有双胞体3和8(及其相应的外部致密纤维)，以及中央对。在许多情况下，在两种方法制备的中段切片中都可以发现具有外部致密纤维3和8的3-中心-8复合体。3-中央-8间隔有时也孤立地出现在主段的横截面上，在那里它仍然附着在纤维鞘上。纤维4到7在高pH条件下挤压产生的鞭毛残留物一般是直的或随机弯曲的。相反，由9-1-2纤维束挤压产生的鞭毛残留物最常在中段区弯曲成钩。虽然钩状构型不依赖于Ca(2+)，但它可能基于相关的机制。9-1-2组纤维的滑动是动力蛋白-微管蛋白在2和3个二联体之间滑动的结果。这种滑动模式似乎在EGTA的活动精子模型中优先激活，但在高pH提取的模型中很少产生滑动。我们得出的结论是，3-中心对-8复合体和相关的外部致密纤维形成了一个I型梁状分区，它不参与滑动，但作为组织平面节拍的结构基础。此外，很明显，根据所采用的治疗方案，某些动力蛋白臂可以被优先激活。这明确地表明，在两个弯曲方向上滑动的微管类型并不相同。
Two distinct patterns of microtubular sliding were observed in rat sperm flagellar axonemes. The particular pattern of sliding was determined by the extraction conditions used to prepare the sperm for axoneme disintegration. Sperm prepared by incubating concentrated suspensions of Triton X-100-extracted sperm at pH 9.0 disintegrated by extruding the doublets and outer dense fibers numbered 4 through 7 in response to Mg-ATP. Sperm prepared by incubating motile Triton X-100-extracted models at 37 degrees C for 1 to 3 hours extruded doublets and outer dense fibers 9, 1 and 2. Axonemes disintegrated by both regimens tended to have doublets 3 and 8 (with their corresponding outer dense fibers), as well as the central pair, in place. In numerous instances, the 3-central-8 complex with outer dense fibers 3 and 8 could be found isolated in midpiece sections prepared from both methods. The 3-central-8 partition was also sometimes seen in isolation in cross-sections of the principal piece where it remained attached to the fibrous sheath. The flagellar remnant produced by extrusion of fibers 4 through 7 under high pH conditions was generally straight or randomly curved. In contrast, the flagellar remnant produced by extrusion of the 9-1-2 bundle of fibers was most often curved into a hook in the midpiece region. While the hook-like configuration was not Ca(2+)-dependent, it may be based on a related mechanism. The sliding of the 9-1-2 group of fibers is a consequence of dynein-tubulin sliding between the 2 and 3 doublets. This sliding pattern appears to be preferentially activated in the motile sperm models in EGTA, but seldom if ever produced sliding in the high-pH-extracted models. We conclude that the 3-central pair-8 complex and associated outer dense fibers form an I-beam-like partition that does not participate in sliding, but acts as a structural foundation for organizing a planar beat. In addition, it is clear that preferential activation of certain dynein arms can be evoked, depending on the treatment regimen employed. This shows definitively that the types of microtubule sliding in the two bend directions are not identical.
参与维持仓鼠精子鞭毛直线度的巯基蛋白的表征。
影响因子：
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作者：
Cornwall,GA;Chang,TS
通讯作者：
Chang,TS