Forever young: the key to rejuvenation during gametogenesis

Abstract

Cell aging is the result of deteriorating competence in maintaining cellular homeostasis and quality control. Certain cell types are able to rejuvenate through asymmetric cell division by excluding aging factors, including damaged cellular compartments and extrachromosomal rDNA circles, from entering the daughter cell. Recent findings from the budding yeast S. cerevisiae have shown that gametogenesis represents another type of cellular rejuvenation. Gametes, whether produced by an old or a young mother cell, are granted a renewed replicative lifespan through the formation of a fifth nuclear compartment that sequesters the harmful senescence factors accumulated by the mother. Here, we describe the importance and mechanism of cellular remodeling at the nuclear envelope mediated by ESCRT-III and the LEM-domain proteins, with a focus on nuclear pore biogenesis and chromatin interaction during gamete rejuvenation.

Keywords: ESCRT-III; LEM-domain; Meiosis; Nuclear pore complex; Replicative lifespan.

Figure 1.

LEM-domain proteins and ESCRT-III regulate NPC sequestration and chromosome segregation during gametogenesis in budding yeast. (A) Selected images from time-lapse microscopy showing the nucleoporin Pom34-GFP (green) localization in wild-type (WT) and vps4 mutant cells. Hta1-mApple (red) marks the chromosomes. The corresponding diagrams shown below detail chromosome movement and GUNC (gametogenesis uninherited nuclear compartment) formation in WT and vps4 mutants during meiosis II. (B) Hypothetical model for LEM protein and ESCRT-III action at the nuclear envelope during gametogenesis in budding yeast. Recruitment of ESCRT-III/Vps4 (shown in purple) by the LEM-domain proteins (red) to the nuclear envelope promotes the disassociation of basket nucleoporins (yellow) from the core. Nuclear pore complexes (NPCs) are shown in green, chromosomes in blue, and the spindle pole body (SPB) in pink.