Hoyer-Fender S, Petersen C, Brohmann H, Rhee K, Wolgemuth D J
University of Göttingen, III. Department of Zoology-Developmental Biology, Germany.
Mol Reprod Dev. 1998 Oct;51(2):167-75. doi: 10.1002/(SICI)1098-2795(199810)51:2<167::AID-MRD6>3.0.CO;2-O.
The outer dense fibers (ODF) of the mammalian sperm tail comprise a unique, specialized, and very prominent structure, consisting of nine fibers surrounding the axoneme. The ODF may play an important but as yet undefined role in sperm morphology, integrity and function. Study of the ODF is hampered by insufficient knowledge of their protein composition and the genetic regulation of their synthesis. We report here on the characterization of cDNAs encoding the Odf2 proteins of outer dense fibers of mouse sperm. We isolated two cDNA clones with variable 5' regions. Variability in sequence is restricted to specific regions in the N-terminal part of the encoded proteins, whereas the C-terminal part is highly conserved in Odf2 proteins both between species and within a species. This variability is confirmed at the protein level. The outer dense fibers could be detected immunologically in total sperm tails allowing a direct comparison of their length in relation to the length of the sperm tail. Odf2 transcripts could be demonstrated in testicular RNA and are restricted to germ cells. The start of transcription is in step 5 spermatids of tubular stage V and the RNA could be detected in the cytoplasm of differentiating spermatids in all subsequent tubular stages.
哺乳动物精子尾部的外周致密纤维（ODF）构成一种独特、特殊且非常显著的结构，由围绕轴丝的九条纤维组成。ODF可能在精子形态、完整性和功能方面发挥重要但尚未明确的作用。由于对其蛋白质组成以及合成的基因调控了解不足，ODF的研究受到了阻碍。我们在此报告对编码小鼠精子外周致密纤维Odf2蛋白的cDNA的特性分析。我们分离出两个5'区域可变的cDNA克隆。序列变异仅限于所编码蛋白质N端的特定区域，而C端在不同物种间以及同一物种内的Odf2蛋白中高度保守。这种变异在蛋白质水平上得到了证实。在外周致密纤维可以在整个精子尾部通过免疫方法检测到，从而能够直接比较它们与精子尾部长度的关系。Odf2转录本可以在睾丸RNA中检测到，并且仅限于生殖细胞。转录起始于管状阶段V的5期精子细胞，在所有后续管状阶段分化中的精子细胞的细胞质中都能检测到该RNA。
