GIP Contributions to the Regulation of Centromere at the Interface Between the Nuclear Envelope and the Nucleoplasm

Abstract

Centromeres are known as specific chromatin domains without which eukaryotic cells cannot divide properly during mitosis. Despite the considerable efforts to understand the centromere/kinetochore assembly during mitosis, until recently, comparatively few studies have dealt with the regulation of centromere during interphase. Here, we briefly review and discuss past and recent advances about the architecture of centromeres and their regulation during the cell cycle. Furthermore, we highlight and discuss new findings and hypotheses regarding the specific regulation of centromeres in both plant and animal nuclei, especially with GIP proteins at the interface between the nuclear envelope and the nucleoplasm.

Keywords: Arabidopsis; GIP; centromere assembly; centromere maintenance; cohesion; nuclear envelope; replication.

FIGURE 1

Hypothetical model depicting the different roles played by GIPs at the nuclear envelope and nucleoplasm interface for centromere regulation in Arabidopsis thaliana. During the G1/S phase, GIPs may contribute to the cohesion establishment/maintenance at centromeres probably through a CTF7/SMC3-mediated mechanism. During the G2 phase, GIPs may participate to the loading/maintenance of CENH3 at centromeres probably through a regulatory pathway complementary to the one proposed for KNL2 (Lermontova et al., 2013). Together, GIPs seem to operate as a multifunctional hub at the nuclear envelope periphery to coordinate centromeric functions and establish with CENP-C a functional kinetochore essential for chromosome segregation.