Cyclic AMP Action During Sperm Function

描述（由申请人提供）：第二信使环AMP （cAMP）调节广泛的细胞活动。它对哺乳动物精子的发生、精子在附睾中的成熟和获能（精子在受精前经历的附睾后成熟过程）至关重要。碳酸氢盐和钙反应的“可溶性”腺苷酸环化酶（SACY）是小鼠生殖细胞和精子中cAMP的主要来源。当Sacy基因被同源重组切除时，结果是男性不育。尽管睾丸内的精子发生似乎不受干扰，但形态正常的精子是不动的。膜渗透性cAMP类似物可以部分恢复运动，突出了cAMP在这一过程中的重要性。然而，这些精子在体外不能使卵子受精，这表明精子仍然有缺陷。为了实现我们的长期目标，了解cAMP及其信号通路在促进哺乳动物精子受精能力中的作用，我们将：1)通过相互精原移植确定Sacy-null表型是否是精子发生和/或附睾成熟过程中发生的事件的结果；2)通过鉴定两种基因型精子的蛋白质差异，研究无sacy精子中鞭毛成角和不动的分子基础；3)确定EPACs （camp激活蛋白家族）对精子运动的作用。如果没有附睾中精子的成熟和精子的获能，受精就不会发生，这一事实强调了该项目的临床意义。虽然这种受精障碍可以通过辅助生殖技术（如胞浆内单精子注射）来绕过，但本应用中详细研究的结果可能允许临床医生修改体外受精和人工授精方法来增强能性。这些研究可能为避孕药物的开发确定新的途径和目标。项目说明：该项目与公共卫生的相关性在于，如果精子没有“失能”，它们就不能使卵子受精。了解SACY在睾丸精子发生、附睾精子成熟和精子获能过程中的作用，将使我们能够提高精子获得受精能力的效率。项目的叙述

DESCRIPTION (provided by applicant): The second messenger cyclic AMP (cAMP) regulates a broad spectrum of cellular activities. It is critical for mammalian spermatogenesis, maturation of sperm in the epididymis, and capacitation, the post-epididymal maturational process that sperm undergo prior to fertilization. The bicarbonate- and calcium-responsive `soluble' adenylyl cyclase (SACY) is the predominant source of cAMP in both mouse germ cells and sperm. When the Sacy gene is ablated by homologous recombination, the result is male infertility. Although spermatogenesis in the testis appears to proceed undisturbed, the morphologically normal sperm are immotile. Motility can be partially rescued with membrane permeable cAMP analogs, highlighting the importance of cAMP in this process. However, these sperm are not able to fertilize eggs in vitro, indicating that the sperm are still defective. To address our long-term goal of understanding the role of cAMP and its signaling pathways in promoting fertilization-competence of mammalian sperm, we will: 1) establish whether the Sacy-null phenotype is the result of events occurring during spermatogenesis and/or the course of epididymal maturation using reciprocal spermatogonial transplantation; 2) examine the molecular bases for the flagellar angulation and immotility seen in Sacy-null sperm by identifying protein differences in the sperm of the two genotypes, and, 3) determine the role that EPACs, a family of cAMP-activated proteins, have on sperm motility. The fact that fertilization does not occur without proper sperm maturation in the epididymis and sperm capacitation emphasizes the clinical significance of this project. Although this block to fertilization can be circumvented by assisted reproductive technologies such as intracytoplasmic sperm injection, the findings from the research detailed in this application may allow the clinician to modify in vitro fertilization and artificial insemination methodologies to enhance capacitation. These studies may identify new pathways and targets for contraceptive development. Project Narrative: The relevance of this project to public health is that if sperm do not 'capacitate', they can not fertilize an egg. Understanding the role of SACY during spermatogenesis in the testis, sperm maturation in the epididymis, and sperm capacitation will allow us to improve the efficacy of sperm becoming fertilization-competent. Project Narrative The relevance of this project to public health is that if sperm do not 'capacitate', they can not fertilize an egg. Understanding the role of SACY during spermatogenesis in the testis, sperm maturation in the epididymis, and sperm capacitation will allow us to improve the efficacy of sperm becoming fertilization-competent.