International Research Fellowship Program: Unraveling Genetic and Nongenetic Causes of Sperm Precedence in Stalk-eyed Flies

国际研究奖学金计划：揭示茎眼果蝇精子优先的遗传和非遗传原因

• 批准号: 0913116
• 负责人: Leanna Birge
• 金额: $ 19.83万
• 依托单位: Birge Leanna M
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0913116&HistoricalAwards=false
• 关键词: International; Research; Fellowship; Program; Unraveling

0913116BirgeThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Leanna M. Birge to work with Dr. Andrew Pomiankowski at University College London in the United Kingdom and with Dr. Gerald Wilkinson at the University of Maryland in the U.S.Female multiple mating creates an arena for competition to occur among ejaculates. In response, males employ a variety of mechanisms to bias their fertilization success, such as incapacitation. However, the importance of incapacitation as a mechanism for sperm precedence is controversial because it is unclear how a male can damage a rival?s ejaculate without also damaging his own. To evaluate the utility of incapacitation and identify its agents, a system is needed in which genetic differences between competitors? ejaculates can be identified. Stalk-eyed flies provide such a system. In Cyrtodiopsis whitei, sperm from males that produce unbiased sex ratios incapacitate sperm from males that produce female-biased sex ratios caused by X chromosome meiotic drive. In this project, we conduct two complementary studies using this system: a test of the robust nature of incapacitation and a molecular characterization of proteins associated with incapacitation. To assess the strength of incapacitation, adult diet is manipulated using a population and protocols developed at University College London and drive and non-drive males are competed in an in vitro sperm viability assay developed at University of Maryland. Analysis of variance is performed across treatments on live/dead sperm counts. A priori, drive males are expected to overcome incapacitation in the low protein diet treatment due to changes in protein composition caused by dietary stress to non-drive males. The molecular portion of the project is conducted at the University of Maryland and focuses on identifying changes in ejaculatory protein profiles associated with incapacitation. A portion of this work includes the construction of expressed sequence tag (EST) libraries from testes and male accessory glands. Tandem mass spectroscopy is performed on three different combinations of seminal vesicle/accessory gland samples as well as an internal standard to identify protein profiles. Tandem mass spectroscopy results are compared to EST libraries and differences between treatments in protein composition and expression are quantified to identify candidate incapacitation genes.Broader impacts of the proposed work include advanced training for the postdoctoral fellow and University of Maryland undergraduate students. In addition, the project fosters international collaboration between the postdoctoral fellow and two senior investigators in the UK and US. Results from this study have the potential to provide insight into sperm development and dysfunction, which have biomedical relevance for understanding causes of male infertility. Finally, a large amount of DNA sequence information is deposited in online repositories, thereby enhancing the ability of other investigators to conduct comparative genomic studies.

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该项目的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Leanna M.Birge博士与英国伦敦大学学院的Andrew Pomiankowski博士和美国马里兰大学的Gerald Wilkinson博士合作的为期24个月的研究奖学金。作为回应，雄性会使用各种机制来偏见他们的受精成功，比如丧失受精能力。然而，作为精子优先机制的丧失能力的重要性存在争议，因为尚不清楚男性如何在不损害自己的情况下射精？S射精。为了评估丧失能力的效用并确定其病原体，需要一个系统，在这个系统中，竞争对手之间的基因差异？射精者可以被辨认出来。柄眼苍蝇提供了这样一种系统。在白色网眼中，来自产生无偏见性别比的雄性的精子使来自产生由X染色体减数分裂驱动引起的女性偏见的性别比的雄性的精子丧失能力。在这个项目中，我们使用这个系统进行了两项补充研究：一项是对丧失能力的健壮性质的测试，另一项是与丧失能力相关的蛋白质的分子特征的测试。为了评估丧失能力的强度，成人的饮食是使用伦敦大学学院开发的种群和方案来操纵的，驾驶和非驾驶的雄性在马里兰大学开发的体外精子存活率测试中进行竞争。对活/死精子计数进行了不同处理间的方差分析。由于饮食压力对非驱动力雄鼠造成的蛋白质组成的变化，驱动力雄鼠有望在低蛋白饮食治疗中克服丧失能力的问题。该项目的分子部分是在马里兰大学进行的，重点是识别与丧失行为能力有关的射精蛋白质谱的变化。这项工作的一部分包括从睾丸和雄性附属腺构建表达序列标签(EST)文库。串联质谱仪对精囊/附腺样本的三种不同组合以及一个内部标准进行检测，以确定蛋白质图谱。串联质谱学结果与EST文库进行比较，并量化处理之间在蛋白质组成和表达方面的差异，以确定候选丧失能力基因。拟议工作的广泛影响包括对博士后研究员和马里兰大学本科生的高级培训。此外，该项目还促进了博士后研究员与英国和美国的两名高级研究人员之间的国际合作。这项研究的结果有可能提供对精子发育和功能障碍的洞察，这对理解男性不育的原因具有生物医学意义。最后，大量的DNA序列信息被存放在在线存储库中，从而增强了其他研究人员进行比较基因组研究的能力。