Human Genome Wide Association Studies have linked SNPs in NEMP1 (Nuclear Envelope Membrane Protein 1) with early menopause (1,2), however it is unclear if NEMP1 has any role in fertility. We show that whole animal loss of NEMP1 homologs in Drosophila, C. elegans, zebrafish and mice lead to sterility or early loss of fertility. Loss of Nemp leads to nuclear shaping defects, most prominently in the germline. Biochemical, biophysical and genetic studies reveal NEMP proteins support the mechanical stiffness of the germline nuclear envelope via formation of a NEMP
EMERIN complex. These data indicate that the germline nuclear envelope has specialized mechanical properties, and that NEMP proteins play essential and conserved roles in fertility.