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: Deletion of nupA led to the generation of diploid or heterokaryotic colonies, indicating that nupA, although poorly conserved, is essential. Using heterokaryon rescue (Osmani etÂ al., 2006b), we identified heterokaryotic colonies that carried both Î”nupA and parental nuclei (Figure 3A). Diagnostic PCR confirmed the presence of the two genetically distinct types of nuclei (Figure 3Ab). Î”nupA mutant spores generated from the heterokaryotic colonies initially germinated and grew at a rate similar to wild-type spores but then stopped growing (Figure 3B) after several rounds of apparently defective mitosis, with nuclear DNA of the Î”nupA cells being missegregated and often clustered (Figure 3C). These phenotypes are very similar to the Î”nup2 mutant (Osmani etÂ al., 2006a), suggesting that Nup2 and NupA could have interÂdependent functions.
Affiliation: Laboratory of Gene Regulation and Development, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.