Spadafora C
Institute of Biomedical Technology, CNR, Rome, Italy.
Bioessays. 1998 Nov;20(11):955-64. doi: 10.1002/(SICI)1521-1878(199811)20:11<955::AID-BIES11>3.0.CO;2-8.
Sperm cells from a variety of species share the spontaneous ability to take up foreign DNA. That feature has been exploited to generate genetically modified animals with variable efficiency in different species. An unexpectedly large set of factors appears to modulate the interaction of sperm cells with exogeneous DNA. The binding is mediated by specific DNA-binding proteins and is antagonized by an inhibitory factor in the seminal fluid. A portion of sperm-bound DNA is internalized in nuclei, a process mediated by CD4 molecules. Sperm interaction with foreign DNA triggers endogenous nuclease(s) that cleaves both the exogenous and the genomic DNA, eventually leading to a cell death process which resembles apoptosis. Internalized foreign DNA sequences reach the nuclear matrix and undergo recombination with chromosomal DNA. From these studies, a surprising network of metabolic functions is beginning to emerge in mature spermatozoa, which are normally repressed and are specifically activated upon exposure to appropriate stimuli.
来自多种物种的精子细胞具有摄取外源DNA的自发能力。这一特性已被用于在不同物种中以不同效率生成转基因动物。似乎有一大组意想不到的因素调节精子细胞与外源DNA的相互作用。这种结合由特定的DNA结合蛋白介导，并受到精液中一种抑制因子的拮抗。一部分与精子结合的DNA被内化到细胞核中，这一过程由CD4分子介导。精子与外源DNA的相互作用会触发内源性核酸酶，该酶会切割外源DNA和基因组DNA，最终导致类似于细胞凋亡的细胞死亡过程。内化的外源DNA序列到达核基质并与染色体DNA发生重组。从这些研究中，一个令人惊讶的代谢功能网络开始在成熟精子中显现出来，这些功能通常受到抑制，并在受到适当刺激时被特异性激活。
