Schultz Nikolaus, Hamra F Kent, Garbers David L
Cecil H. and Ida Green Center for Reproductive Biology Sciences, Howard Hughes Medical Institute and Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12201-6. doi: 10.1073/pnas.1635054100. Epub 2003 Oct 2.
Understanding mammalian spermatozoan development and the events surrounding fertilization has grown slowly, in part because of uncertainty about the number and identity of the cellular components involved. Determination of those transcripts expressed specifically by germ cells should provide an inclusive list of probable critical proteins. Here, total mouse testis transcript profiles were trimmed of transcripts found in cultures enriched in Sertoli or interstitial cells to yield a germ cell-enriched transcript profile. Monitoring of changes of this profile in the developing testis identified 1,652 genes whose transcript abundance increased markedly coincident with the onset of meiosis. Remarkably, 351 of these genes (approximately equal to 20%) appear to be expressed only in the male germline. Germ cell-specific transcripts are much less common earlier in testis development. Further analysis of the UniGene EST database coupled with quantitative PCR indicates that approximately 4% of the mouse genome is dedicated to expression in postmeiotic male germ cells. Most or many of the protein products of these transcripts are probably retained in mature spermatozoa. Targeted disruption of 19 of these genes has indicated that a majority have roles critical for normal fertility. Thus, we find an astonishing number of genes expressed specifically by male germ cells late in development. This extensive group provides a plethora of potential targets for germ cell-directed contraception and a staggering number of candidate proteins that could be critical for fertilization.
对哺乳动物精子发育以及受精相关事件的了解进展缓慢，部分原因是涉及的细胞成分数量和身份存在不确定性。确定生殖细胞特异性表达的转录本应能提供一份可能的关键蛋白质的完整清单。在此，从小鼠睾丸的总转录本谱中去除在支持细胞或间质细胞富集培养物中发现的转录本，以产生生殖细胞富集的转录本谱。监测发育中的睾丸中该谱的变化，鉴定出1652个基因，其转录本丰度在减数分裂开始时显著增加。值得注意的是，这些基因中有351个（约20%）似乎仅在雄性生殖系中表达。生殖细胞特异性转录本在睾丸发育早期要少见得多。对UniGene EST数据库的进一步分析以及定量PCR表明，小鼠基因组中约4%专门用于减数分裂后雄性生殖细胞中的表达。这些转录本的大多数或许多蛋白质产物可能保留在成熟精子中。对其中19个基因的靶向破坏表明，大多数基因对正常生育能力具有关键作用。因此，我们发现发育后期雄性生殖细胞特异性表达的基因数量惊人。这个庞大的基因群体为生殖细胞导向的避孕提供了大量潜在靶点，以及数量惊人的可能对受精至关重要的候选蛋白质。
