Nup2 requires a highly divergent partner, NupA, to fulfill functions at nuclear pore complexes and the mitotic chromatin region.
Bottom Line: These mitotic problems are not caused by overall defects in mitotic NPC disassembly-reassembly or general nuclear import.However, without Nup2 or NupA, although the SAC protein Mad1 locates to its mitotic locations, it fails to locate to NPCs normally in G1 after mitosis.Collectively the study provides new insight into the roles of Nup2 and NupA during mitosis and in a surveillance mechanism that regulates nucleokinesis when mitotic defects occur after SAC fulfillment.
Affiliation: Laboratory of Gene Regulation and Development, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.Show MeSH
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Mentions: As mentioned above, during A. nidulans mitosis, NPCs partially disassemble, and nuclear proteins, such as NLS-DsRed, disperse from nuclei and locate throughout the cell (De Souza et al., 2004; Osmani et al., 2006a; De Souza and Osmani, 2009). Dispersal of NLS-DsRed therefore acts as a marker for entry into mitosis and its nuclear reimport a marker for mitotic exit into G1. In a manner identical to Nup2, NupA-GFP was found to translocate from NPCs to concentrate to the mitotic chromatin region until cells exit mitosis (Figure 4A). Accordingly, NupA-GFP and the chromatin marker histone H1–monomeric red fluorescent protein (mRFP) localized together during mitosis (Figure 4B), and, as expected from their copurification, NupA-GFP and Nup2-ChRFP localize together at interphase NPCs and the mitotic chromatin region (Figure 4C).
Affiliation: Laboratory of Gene Regulation and Development, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.