growth-arrest-specific protein 2 inhibits cell division in xenopus embryosgrowth-arrest-specific蛋白2在非洲爪蟾蜍胚胎抑制细胞分裂.pdfVIP

Growth-Arrest-Specific Protein 2 Inhibits Cell Division in Xenopus Embryos 1 2 2 2 1,2 Tong Zhang *, Bama Dayanandan , Isabelle Rouiller , Elizabeth J. Lawrence , Craig A. Mandato * 1 Department of Biology, McGill University, Montreal, Quebec, Canada, 2 Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada Abstract Background: Growth-arrest-specific 2 gene was originally identified in murine fibroblasts under growth arrest conditions. Furthermore, serum stimulation of quiescent, non-dividing cells leads to the down-regulation of gas2 and results in re-entry into the cell cycle. Cytoskeleton rearrangements are critical for cell cycle progression and cell division and the Gas2 protein has been shown to co-localize with actin and microtubules in interphase mammalian cells. Despite these findings, direct evidence supporting a role for Gas2 in the mechanism of cell division has not been reported. Methodology and Principal Findings: To determine whether the Gas2 protein plays a role in cell division, we over- expressed the full-length Gas2 protein and Gas2 truncations containing either the actin-binding CH domain or the tubulin- binding Gas2 domain in Xenopus laevis embryos. We found that both the full-length Gas2 protein and the Gas2 domain, but not the CH domain, inhibited cell division and resulted in multinucleated cells. The observation that Gas2 domain alone can arrest cell division suggests that Gas2 function is mediated by microtubule binding. Gas2 co-localized with microtubules at the cell cortex of Gas2-injected Xenopus embryos using cryo-confocal microscopy and co-sedimented with microtubules in cytoskeleton co-sedimen