The Malleable Nature of the Budding Yeast Nuclear Envelope: Flares, Fusion, and Fenestrations

Abstract

In eukaryotes, the nuclear envelope (NE) physically separates nuclear components and activities from rest of the cell. The NE also provides rigidity to the nucleus and contributes to chromosome organization. At the same time, the NE is highly dynamic; it must change shape and rearrange its components during development and throughout the cell cycle, and its morphology can be altered in response to mutation and disease. Here we focus on the NE of budding yeast, Saccharomyces cerevisiae, which has several unique features: it remains intact throughout the cell cycle, expands symmetrically during interphase, elongates during mitosis and, expands asymmetrically during mitotic delay. Moreover, its NE is safely breached during mating and when large structures, such as nuclear pore complexes and the spindle pole body, are embedded into its double membrane. The budding yeast NE lacks lamins and yet the nucleus is capable of maintaining a spherical shape throughout interphase. Despite these eccentricities, studies of the budding yeast NE have uncovered interesting, and likely conserved, processes that contribute to NE dynamics. In particular, we discuss the processes that drive and enable NE expansion and the dramatic changes in the NE that lead to extensions and fenestrations.

Integrative structure and functional anatomy of a nuclear pore complex

“…5E). Collectively, these flexible connectors may serve to permit limited movement of the more rigid modules with respect to each other, thereby providing the NPC with another degree of flexibility in response to deformation 27 .…”

Nuclear Export Through Nuclear Envelope Remodeling inSaccharomyces cerevisiae

“…Unlike the requirement for the AAA+ ATPase Torsin in Drosophila and mammalian cells , yeast contain no recognizable Torsin homolog. Likewise, the INM of yeast is not supported by a lamin-type structure (Meseroll and Cohen-Fix, 2016). Thus, the molecular details of granule invagination and scission into the perinuclear space appear to differ between species.…”

The budding yeast RSC complex maintains ploidy by promoting spindle pole body insertion

“…The NPC distribution changes from the typical uniform distribution at the nuclear periphery (time = 0) to an abnormal and punctate distribution at later times. The abnormal NPC distribution is an indicator of NPC and/or nuclear envelope stress (Titus et al, 2010; Meseroll and Cohen-Fix, 2016). We tested whether overexpression of NBP1 rescued the NPC localization by quantifying pixel intensity in at least 100 cells containing Nic96-GFP or Nup170-GFP before and after Htl1 depletion.…”