Francolini M, Lavitrano M, Lamia C L, French D, Frati L, Cotelli F, Spadafora C
Department of Biology, University of Milan, Italy.
Mol Reprod Dev. 1993 Feb;34(2):133-9. doi: 10.1002/mrd.1080340204.
Mature sperm cells have the spontaneous capacity to take up exogenous DNA. Such DNA specifically interacts with the subacrosomal segment of the sperm head corresponding to the nuclear area. Part of the sperm-bound foreign DNA is further internalized into nuclei. Using end-labelled plasmid DNA we have found that 15-22% of the total sperm bound DNA is associated with nuclei as determined on isolated nuclei. On the basis of autoradiographic analysis, nuclear permeability to exogenous DNA seems to be a wide phenomenon involving the majority of the sperm nuclei. In fact, the foreign DNA, incubated with sperm cells for different lengths of time, is found in 45% (10 min) to 65% (2 hr) of the sperm nuclei. Ultrastructural autoradiography on thin sections of mammalian spermatozoa, preincubated with end-labelled plasmid DNA, shows that the exogenous DNA is internalized into the nucleus. This conclusion is further supported by ultrastructural autoradiographic analysis on thin sections of nuclei isolated from spermatozoa preincubated with end-labelled DNA.
成熟精子细胞具有摄取外源DNA的自发能力。此类DNA特异性地与精子头部对应核区域的顶体下节段相互作用。部分与精子结合的外源DNA会进一步内化进入细胞核。使用末端标记的质粒DNA，我们发现，在分离出的细胞核上测定，与精子结合的总DNA中15% - 22%与细胞核相关联。基于放射自显影分析，对外源DNA的核通透性似乎是一种广泛现象，涉及大多数精子细胞核。事实上，与精子细胞孵育不同时长的外源DNA，在45%（10分钟）至65%（2小时）的精子细胞核中被发现。对用末端标记质粒DNA预孵育的哺乳动物精子薄切片进行超微结构放射自显影显示，外源DNA被内化进入细胞核。对用末端标记DNA预孵育的精子分离出的细胞核薄切片进行超微结构放射自显影分析进一步支持了这一结论。
