Mouse oocytes injected with testicular spermatozoa or round spermatids can develop into normal offspring.
Mouse oocytes injected with testicular spermatozoa or round spermatids can develop into normal offspring.
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发表时间：
1995-08
期刊：
影响因子：
4.6
通讯作者：
Y. Kimura;Ryuzo Yanagimachi
中科院分区：
文献类型：
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作者：
Y. Kimura;Ryuzo Yanagimachi
基因组印记发生在配子发生过程中的雄性和雌性配子中，但印记开始和结束的确切时间尚不清楚。在本研究中，我们将睾丸精子和圆形精子细胞的细胞核注射到成熟的小鼠卵母细胞中，以观察这些细胞核是否能够参与受精和正常的胚胎发育。如果注射的卵母细胞发育成正常的生育后代，则所使用的雄性生殖细胞中的印记必须在注射时完成。注射睾丸精子的小鼠卵母细胞中有92%存活，其中94%正常受精（第二极体排出和雌雄原核形成）。当44个这样产生的二细胞胚胎被转移到5个寄养母亲，24个（54.5%）发育成正常的后代。与睾丸精子不同，圆形精子细胞无法激活卵母细胞，因此必须在精子细胞注射之前或之后人工激活卵母细胞。当卵母细胞首先被电流激活，然后单独注射单个精子细胞核时，获得了最高的正常受精率（77%）。当131个两细胞胚胎被转移到15个寄养母亲时，37个（28.2%）达到足月。除两个外，所有人都长成了健康的成年人。因此，看来小鼠生精细胞中的配子印迹在精子发生开始之前就已经完成。在所采用的实验条件下，精子细胞核在产生正常后代方面不如睾丸精子核有效，但这可能是由于技术而不是固有的问题。
Genomic imprinting occurs in both male and female gametes during gametogenesis, but the exact time when imprinting begins and ends is unknown. In the present study we injected nuclei of testicular spermatozoa and round spermatids into mature mouse oocytes to see whether these nuclei are able to participate in syngamy and normal embryonic development. If the injected oocytes develop into normal fertile offspring, imprinting in the male germ cells used must have been completed by the time of injection. Ninety-two percent of mouse oocytes injected with testicular spermatozoa survived and 94% of these were fertilized normally (extrusion of the second polar body and formation of male and female pronuclei). When 44 two-cell embryos so created were transferred to 5 foster mothers, 24 (54.5%) developed into normal offspring. Unlike testicular spermatozoa, round spermatids could not activate the oocytes, and therefore the oocytes had to be activated artificially either before or after spermatid injection. The highest rate (77%) of normal fertilization was obtained when the oocytes were first activated by electric current, then injected individually with a single spermatid nucleus. When 131 two-cell embryos were transferred to 15 foster mothers, 37 (28.2%) reached full term. All but two grew into healthy adults. Thus, it would appear that gametic imprinting in mouse spermatogenic cells is completed before spermiogenesis begins. Under the experimental conditions employed, spermatid nuclei were less efficient than testicular sperm nuclei in producing normal offspring, but perhaps this was due to technical rather than inherent problems.