Cell cycle-dependent nuclear envelope component required for embryonic mitosis. In the nuclear envelope during interphase to metaphase. And in the nucleoplasm and cytoplasm during anaphase and telophase. Maternal protein synthesized during postoogenic maturation and persisting throughout embryogenesis. The OPA repeat-containing and the Ser/Thr-rich regions might be involved in protein-protein interactions with the major protein-rich layer of the nuclear envelope.