Friday, May 2, 2025
5/2/2025
Sperm striated columns composition - Summary Dividing somatic cells requires an evolutionary, structurally, and compositionally conserved centrosome and cilium, containing two barrel-shaped centrioles and pericentriolar material, to function correctly. The centrosome organizes the cell's microtubule cytoskeleton, and the cilium acts as a sensory organelle. In contrast, the sperm, egg, and zygote either don’t have centrosomes and cilia or have centrosomes and cilia of unique structure and composition. The egg has no centrosomes or cilia; the spermatozoon has one barrel-shaped centriole, one atypical fan-shaped centriole connected to a motile cilium (flagella), and specialized pericentriolar material named the striated columns. The zygote has a centrosome that contains the sperm centrioles and assembles a pericentriolar material from cytosolic egg proteins. The sperms' striated columns connect the sperm tail to the head and are thought to be degraded in the zygote. However, recent bovine studies suggest that the striated columns have two more functions: one, forming a dynamic link that transmits sperm tail beating to generate head twitching in the spermatozoa, and second, participating in zygote centrosome function. Currently, the need for a molecular reporter of the striated columns hinders studying these two new proposed functions. The activities presented here close this gap by examining the composition of striated columns in bovine spermatozoa and zygotes. The long-term goal is to understand the contribution of sperm centrosomes, including the striated columns, to infertility and early pregnancy loss. This application aims to identify striated columns’ markers to enable future testing of the central hypothesis that striated columns are an essential component of the dynamic spermatozoon head-tail link and the zygote centrosome. The specific aim is to identify striated columns’ biomarkers that enable testing the striated columns' contribution to the spermatozoa dynamic basal complex and the zygote centrosome. Our working hypothesis is that centrosomal components, such as CEP135 and CP110, are novel components of the striated columns; they will be detected in the zygote centrosome using immunofluorescent confocal microscopy, they will exhibit sperm movement-mediated deformation detected using super-resolution microscopy, and there are other novel components of the striated columns. We anticipate that these studies will demonstrate that striated columns’ proteins’ locations will coordinate with sperm head-tail movement and that striated columns’ components are retained in the zygote centrosome. This anticipated finding will form the basis for more directed studies on the role of the striated columns in the spermatozoa and zygote. Ultimately, knowledge gained from this basic research will form a basis for additional insights into potential new causes of male infertility, early-stage miscarriages, and developmental diseases.
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