Inner nuclear envelope protein involved in nuclear fission, which is achieved via local disassembly of nuclear pores within the narrow bridge that links segregating daughter nuclei (PubMed:32848252). Les1 restricts the process of local nuclear envelope breakdown to the bridge midzone to prevent the leakage of material from daughter nuclei during mitosis (PubMed:32848252). Concentrates at the stalk of each daughter nucleus during anaphase.