Shankar Goutham, Uppangala Shubhashree, Adiga Satish K, Willard Belinda, Sagar Bhadravathi K C, Titus Ruth S K, Marathe Gopal K
Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru 570006, Karnataka, India.
Division of Clinical Embryology, Kasturba Medical College, Manipal University, Manipal 576104, Karnataka, India.
Reprod Fertil Dev. 2018 May;30(5):744-751. doi: 10.1071/RD17292.
Female sperm storage is an intriguing adaptation exhibited by a wide array of both vertebrates and invertebrates. The mechanisms underlying female sperm storage have remained elusive. Using the Indian garden lizard Calotes versicolor as a model organism, we investigated the role of low and high molecular weight factors in this phenomenon. Previously, we demonstrated three distinct phases of the reproductive cycle in this animal with live, motile spermatozoa recovered from the uterovaginal region during the reproductive phase. In the present study, we analysed the uterovaginal contents using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified an abundant protein band corresponding to ~55 kDa regardless of the phase of the reproductive cycle. Analysis of the purified protein by liquid chromatography-tandem mass spectrometry suggested a unique protein without any homology to the National Center for Biotechnology Information database. Exogenous addition of this protein to washed spermatozoa derived from the epididymis reversibly inhibited sperm motility in a concentration- and time-dependent manner, suggesting it plays a key role in sperm storage. These studies are likely to offer new avenues to unravel the secrets of female sperm storage seen across the animal taxa and may have novel applications not only in reproductive biology, but also in general cell storage and preserving endangered animal species.
雌性精子储存是一种广泛存在于脊椎动物和无脊椎动物中的有趣适应性现象。雌性精子储存背后的机制一直难以捉摸。我们以印度蜓蜥（Calotes versicolor）作为模式生物，研究了低分子量和高分子量因子在这一现象中的作用。此前，我们证明了这种动物生殖周期的三个不同阶段，在生殖阶段可从子宫阴道区域回收存活且有活力的精子。在本研究中，我们使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析了子宫阴道内容物，发现无论生殖周期处于哪个阶段，都有一条对应约55 kDa的丰富蛋白条带。通过液相色谱-串联质谱对纯化蛋白进行分析，结果表明这是一种独特的蛋白，与美国国立生物技术信息中心数据库中的任何蛋白均无同源性。将这种蛋白外源添加到来自附睾的洗涤精子中，会以浓度和时间依赖性方式可逆地抑制精子活力，这表明它在精子储存中起关键作用。这些研究可能为揭开动物类群中普遍存在的雌性精子储存之谜提供新途径，不仅可能在生殖生物学中有新应用，而且在一般细胞储存和保护濒危动物物种方面也可能有新应用。
