Jager S, Wijchman J, Kremer J
Department of Obstetrics and Gynaecology, University Hospital, Groningen, The Netherlands.
J Exp Zool. 1990 Dec;256(3):315-22. doi: 10.1002/jez.1402560311.
We report heparin-induced decondensation of human, mouse, and bull sperm nuclei. Decondensation did not occur if the spermatozoa were intact but only if the membranes were severely damaged by freezing and thawing or by treatment with a detergent. If a disulphide bond reducing agent (thiol) was absent, decondensation of human sperm nuclei was usually a relatively slow process, with large interindividual variation. Mouse and bull sperm nuclei did not decondense in the absence of a thiol. With a thiol relatively low concentrations of heparin induced a rapid decondensation of the sperm nuclei of all three species. The decondensation activity was not specific for heparin; other polyanions were also active, with heparin being the most effective compound. It is supposed that heparin and other polyanions induce sperm nuclear decondensation because they deplete protamines from the chromatin. Thus the negatively charged phosphate groups of the DNA are no longer opposed by positively charged protamines. Consequently the mutual repulsion of unopposed phosphate groups causes the DNA molecules to stretch, which results in an increase of the sperm nuclear volume. Since heparin and other polyanions induce decondensation under physiological pH and temperature, polyanions might also be active in the oocyte.
我们报道了肝素诱导的人、小鼠和公牛精子细胞核解聚现象。如果精子完整，则不会发生解聚，只有当细胞膜因冻融或用去污剂处理而受到严重损伤时才会发生解聚。如果没有二硫键还原剂（硫醇），人精子细胞核的解聚通常是一个相对缓慢的过程，个体间差异较大。在没有硫醇的情况下，小鼠和公牛精子细胞核不会解聚。使用硫醇时，相对低浓度的肝素会诱导所有这三个物种的精子细胞核快速解聚。这种解聚活性并非肝素所特有；其他多阴离子也有活性，其中肝素是最有效的化合物。据推测，肝素和其他多阴离子诱导精子细胞核解聚是因为它们从染色质中耗尽了鱼精蛋白。因此，DNA带负电荷的磷酸基团不再受到带正电荷的鱼精蛋白的对抗。结果，未受对抗的磷酸基团之间的相互排斥导致DNA分子伸展，从而导致精子细胞核体积增大。由于肝素和其他多阴离子在生理pH值和温度下诱导解聚，多阴离子在卵母细胞中可能也具有活性。
