During spermiogenesis, early round spermatids differentiate into specialized spermatozoa through an extensive reshaping of the nucleus driven by coordinated cytoskeletal and chromatin-based mechanisms. In mammals, this process critically relies on the transient manchette, a microtubule-based structure that remodels the spermatid nucleus and serves a track to transport material required for flagellum assembly. However, the existence, organization, and molecular composition of such a structure in other vertebrates have remained poorly investigated. Here, we establish that an organized microtubule network is present in Xenopus spermatids and shares key architectural and molecular hallmarks of the mammalian manchette. We further uncover a large structural heterogeneity of spermatid microtubules, with variable protofilament numbers, skew angles, and lattice organizations. We reveal the presence of a Spaca9–Saxo2 internal scaffold in spermatid microtubules, suggesting an internal reinforcement mechanism necessary for extensive nuclear reshaping and cytoplasm remodeling.
Simple Summary Spermatogenesis in Drosophila melanogaster provides a powerful model for understanding how a round germ cell is transformed into a highly elongated and functional sperm cell. Previous studies have identified many factors involved in sperm tail elongation and individualization, but these processes are oft...
Yang Fang, Jia-Xin Yin, Li-Ping Chen et al.· Biology· 0 citations
Yolk-cytoplasm segregation is among the earliest spatial organization events in the developing embryo of many oviparous animals. The segregation process is intimately linked to early embryonic cleavage and pattern formation, and exhibits a wide range of spatial and temporal diversity. However, the underlying cytoskelet...
In situ cryo-electron tomography in human sperm cells is used to elucidate the molecular architecture of nuclear proteasomes, which cluster in DNA-free, nuclear cavities within the sperm nucleus, and resolves a native peptide in the catalytic β2 subunit, providing insight into the proteolysis mechanism and PA200-mediat...
P. Kolata, Ália dos Santos, Oliver Knowles et al.· Nature Structural & Molecula...· 0 citations
The morphogenesis of developing tissues relies on extensive cellular rearrangements in shape, position, and identity. A key process in reshaping tissues is cell intercalation-driven elongation, where epithelial cells align and intercalate along a common axis. Typically, analyses focus on how peripheral cortical forces...
Left-right asymmetry in vertebrate embryos is established by the left-right organizer (LRO), with the zebrafish Kupffer's vesicle (KV) providing a tractable model for studying de novo epithelial morphogenesis. During KV formation, dorsal forerunner cells (DFCs) initially form polarized attachments to the enveloping lay...
Yi-Ling Lan, Yan Wu, Miriam Athena Allred et al.· Journal of Cell Science· 1 citation
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