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J Cell Biol January 21, 2013; 200 (2): 151-61.
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Chromosomal gain promotes formation of a steep RanGTP gradient that drives mitosis in aneuploid cells.

Hasegawa K , Ryu SJ , Kaláb P .

Many mitotic factors were shown to be activated by Ran guanosine triphosphatase. Previous studies in Xenopus laevis egg extracts and in highly proliferative cells showed that mitotic chromosomes were surrounded by steep Ran guanosine triphosphate (GTP) concentration gradients, indicating that RanGTP-activated factors promote spindle assembly around chromosomes. However, the mitotic role of Ran in normal differentiated cells is not known. In this paper, we show that although the steep mitotic RanGTP gradients were present in rapidly growing cell lines and were required for chromosome congression in mitotic HeLa cells, the gradients were strongly reduced in slow-growing primary cells, such as HFF-1 fibroblasts. The overexpression of RCC1, the guanine nucleotide exchange factor for Ran, induced steeper mitotic RanGTP gradients in HFF-1 cells, showing the critical role of RCC1 levels in the regulation of mitosis by Ran. Remarkably, in vitro fusion of HFF-1 cells produced cells with steep mitotic RanGTP gradients comparable to HeLa cells, indicating that chromosomal gain can promote mitosis in aneuploid cancer cells via Ran.

PubMed ID: 23319601
PMC ID: PMC3549973
Article link: J Cell Biol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: efnb3 gnl3 mapre3 me3 mtor ntmt1 ran rangap1 rcc1

Article Images: [+] show captions
References [+] :
Ai, Hue-shifted monomeric variants of Clavularia cyan fluorescent protein: identification of the molecular determinants of color and applications in fluorescence imaging. 2008, Pubmed