Sperm-egg Interactions in Caenorhabditis Elegans

Singson 0000182线虫的生殖生物学有助于识别影响精子而不影响其他细胞的突变。 这为确定精卵相互作用所需的精子成分提供了一个独特的机会。 spe-9基因突变的蠕虫产生具有野生型形态和运动性的精子，即使在配子之间接触后也不能使卵母细胞受精。 因此，spe-9功能的破坏影响配子识别、粘附、信号传导和/或融合。 spe-9基因编码精子跨膜蛋白，其胞外结构域含有10个表皮生长因子（EGF）样重复序列。 包含EGF样基序的蛋白质的共同特征是它们参与细胞外功能，例如粘附和配体-受体相互作用。 此外，预测的SPE-9蛋白的总体结构与跨膜受体的Notch/LIN-12/GLP-1家族的配体的结构相似。 这些结果表明SPE-9在受精所需的专门细胞-细胞相互作用中起作用。 为了更好地了解SPE-9在受精过程中的作用，我们将进行几项研究。 免疫荧光将用于定位精子中的SPE-9蛋白，并揭示配子相互作用的重要细胞区域。 将进行突变分析实验，以确定SPE-9蛋白的重要功能结构域。 最后，spe-9的基因外抑制基因将被分离出来，以确定其他涉及蠕虫精卵相互作用的基因。 这项工作将为其他生物的受精概念和补充研究提供新的见解。

Singson0000182 The reproductive biology of the nematode worm Caenorhabditis elegans facilitates the identification of mutations that affect sperm and no other cells. This provides a unique opportunity to define sperm components required for sperm-egg interactions. Worms with mutations in the spe-9 gene produce spermatozoa with wild type morphology and motility that cannot fertilize oocytes even after contact between gametes. Therefore, disruption of spe-9 function affects either gamete recognition, adhesion, signaling and/or fusion. The spe-9 gene encodes a sperm transmembrane protein with an extracellular domain that contains ten epidermal growth factor (EGF)-like repeats. A common feature of proteins that include EGF-like motifs is their involvement in extracellular functions such as adhesive and ligand-receptor interactions. Additionally, the overall structure of the predicted SPE-9 protein is similar to that of ligands for the Notch/LIN-12/GLP-1 family of transmembrane receptors. These results suggest that SPE-9 functions in the specialized cell-cell interactions required for fertilization. In order to gain a better understanding of the role of SPE-9 during fertilization we will follow several lines of investigation. Immunofluorescence will be used to localize the SPE-9 protein in sperm and reveal the cellular region important for gamete interactions. Mutation analysis experiments will be conducted in order to determine important functional domains of the SPE-9 protein. Finally, extragenic suppressors of spe-9 will be isolated in order to identify additional genes involved in worm sperm-egg interactions. This work will provide new insights into conception and complement studies of fertilization in other organisms.