Mitochondrial Remodeling, Cytoskeletal Dynamics, and Translational Control During Drosophila Spermatid Elongation: An Integrative Review.

Spermatogenesis in Drosophila melanogaster is a classical model for studying cell polarity establishment, organelle remodeling, and extreme cellular morphogenesis. Spermatid elongation involves a series of highly coordinated dynamic events, including nuclear polarization, axonemal extension, mitochondrial remodeling, and individualization-mediated cytoplasmic clearance. Current studies have largely focused on individual structures, molecules, or pathways, resulting in a fragmented understanding of this process and a lack of an integrated framework that links mitochondrial function, cytoskeletal dynamics, and temporal translational regulation. Based on existing evidence, this review organizes current findings into three regulatory layers involving mitochondrial remodeling, cytoskeletal dynamics, and post-transcriptional translational control. Mitochondrial remodeling provides structural and metabolic support for sperm-tail formation, cytoskeletal processes execute axoneme organization and individualization, and post-transcriptional regulation controls the timing of protein production. Experimental evidence is strongest for mechanisms operating within each layer, whereas direct molecular coupling among the three layers remains incompletely established. We therefore present this model as a working framework rather than an established causal pathway. This framework helps organize current knowledge of extreme cellular differentiation and provides a basis for comparative studies of spermatogenesis and selected mechanisms associated with human male infertility.