Jones R
Oxf Rev Reprod Biol. 1989;11:285-337.
Identification of molecules or factors on spermatozoa that are involved in the recognition and binding to the zona pellucida of the egg is one of the central problems in current research on mammalian fertilization. This information is important, not just from the standpoint of scientific interest, but also for treatment of male infertility and design of future contraceptive technology. One of the most informative approaches to solving this puzzle has been to study the maturation of spermatozoa in the epididymis. The gradual development of motility and zona-binding capacity by spermatozoa after they leave the testis affords an opportunity to investigate what distinguishes a fertile from an infertile spermatozoon and what mechanisms are involved in the transformation from one state to the other. This chapter has reviewed some of the current information on sperm maturation in the epididymis and attempted to correlate it with concepts emerging from in vitro fertilization experiments. Emphasis has been placed on mechanistic aspects of maturation changes to the sperm plasma membrane, not only because in many species it is the surface membrane that encounters the zona and it is therefore likely to be the site of potential recognition molecules, but also because the plasma membrane influences many intracellular events and has a bearing on the maturation of the nucleus and axoneme as well. An example of the latter is shown by the induction of motility in demembranated testicular sperm by the addition of ATP and Mg2+ (Mohri and Yanagimachi 1980; White and Voglmayr 1986). This suggests that the motor apparatus for motility is essentially present in immature spermatozoa and that one of the requirements for it to become fully operative are subtle alterations to the permeability properties of the plasma membrane. A similar mechanism may also be true of the maturing sperm nucleus to which only passing reference has been made here. Very little is known about this aspect of sperm maturation beyond the increasing stabilization of the nucleoprotein by formation of disulphide bonds (Bedford 1975). The fact that isolated heads from immature spermatozoa fail to form pronuclei if injected directly into the egg (Uehara and Yanagimachi 1977) may explain, in part, the high embryonic mortality observed when not fully mature spermatozoa are induced to fertilize eggs (Orgebin-Crist et al. 1975). Thus maturation events within the nucleus are just as important as those on the surface membrane.(ABSTRACT TRUNCATED AT 400 WORDS)
鉴定精子上参与识别和结合卵子透明带的分子或因子，是当前哺乳动物受精研究的核心问题之一。这一信息不仅从科学兴趣的角度来看很重要，对于男性不育症的治疗和未来避孕技术的设计也很重要。解决这个谜题最具启发性的方法之一是研究附睾中精子的成熟过程。精子离开睾丸后，其运动能力和与透明带结合能力的逐渐发展，为研究区分可育精子和不育精子的因素以及从一种状态转变为另一种状态所涉及的机制提供了机会。本章回顾了目前关于附睾中精子成熟的一些信息，并试图将其与体外受精实验中出现的概念联系起来。重点放在了精子质膜成熟变化的机制方面，这不仅是因为在许多物种中，是表面膜接触透明带，因此它很可能是潜在识别分子的位点，还因为质膜影响许多细胞内事件，并且对细胞核和轴丝的成熟也有影响。后者的一个例子是，通过添加ATP和Mg2+可诱导去膜睾丸精子产生运动（Mohri和柳町隆造，1980年；White和Voglmayr，1986年）。这表明运动的动力装置在未成熟精子中基本存在，而使其完全发挥作用的条件之一是质膜通透性特性的细微改变。类似的机制可能也适用于成熟中的精子细胞核，本文仅对此作了简要提及。除了通过形成二硫键使核蛋白越来越稳定外（贝德福德，1975年），关于精子成熟的这方面知之甚少。未成熟精子分离出的头部如果直接注入卵子中无法形成原核（上原和柳町隆造，1977年），这一事实可能部分解释了未完全成熟的精子诱导卵子受精时观察到的高胚胎死亡率（奥尔热班 - 克里斯特等人，1975年）。因此，细胞核内的成熟事件与表面膜上的成熟事件同样重要。（摘要截选至400字）
