Tom70-mediated mitochondria-nuclear envelope contacts regulate nuclear pore complex inheritance during gametogenesis

Abstract

Gametogenesis rejuvenates the cellular lineage and excludes senescence-associated factors from gametes. In Saccharomyces cerevisiae, this involves sequestration of nuclear constituents into the Gametogenesis-Uninherited Nuclear Compartment (GUNC), which is excluded from gametes. Here we identify the conserved mitochondrial import receptor Tom70 as a key regulator of GUNC-mediated exclusion. Loss of TOM70 disrupts the sequestration of nuclear pore complexes, but not senescence-associated aggregates and nucleolar components, into the GUNC. Tom70s role appears independent of its canonical function in mitochondrial import and instead reflects a meiosis-specific requirement for mitochondria-nuclear envelope tethering. During meiosis II, Tom70 concentrates around the GUNC, where it recruits the nuclear envelope tethering protein Cnm1. Loss of CNM1 partially phenocopies tom70{Delta}, consistent with parallel tethering interactions. These findings uncover a previously unrecognized organelle contact-dependent pathway that remodels the nuclear envelope to support selective nuclear inheritance. More broadly, they highlight how organelle contacts integrate with nuclear quality control to safeguard gamete integrity.