Nucleoskeletal Proteins in Early Embryogenesis.

Embryogenesis begins with fertilization, resulting in a totipotent zygote that undergoes a complex series of cellular and molecular events toward the development of a complete organism. During this period, critical events such as zygotic genome activation and cell fate specification occur, characterized by dynamic changes in gene expression programs. Regulation of gene expression is generally explained by chromatin-based mechanisms orchestrated in nuclei. To note, non-chromatin nuclear proteins, referred to as nucleoskeletal proteins, emerge as key players for shaping nuclear and chromatin structures. The nucleoskeleton consists of multiple proteins, and its dynamics are important for establishing cell-type-specific nuclear structure, genome organization, and gene expression patterns. Recent studies have highlighted that nucleoskeletal proteins, particularly lamins and nuclear actin, play diverse and critical roles during early embryogenesis. Furthermore, a growing body of evidence suggests that nuclear architecture itself can actively influence gene expression and embryonic development. In this review, we focus on the nuclear structure of early vertebrate embryos from the viewpoint of the nucleoskeleton. We summarize current findings regarding the dynamics and functions of nucleoskeletal proteins during embryogenesis and further discuss how these constitutional components can affect gene expression and developmental programs.