Supplementary MaterialsFigure 1source data 1: Mean values of spindle length and dynamics. the control of nmt promoters with different strength. Data was collected from three independent experiments. elife-42182-fig5-data1.docx (13K) DOI:?10.7554/eLife.42182.020 Figure 6source data 1: Mean values of Ase1-GFP intensity and signal length. Mean values and corresponding standard deviations of Ase1-GFP intensity and Ase1-GFP signal length in cells. Data obtained from n analyzed cells (wee1-50: n?=?24, wt: n?=?28, cdc25-22: n?=?30) was collected from three independent experiments. elife-42182-fig6-data1.docx (12K) DOI:?10.7554/eLife.42182.026 Supplementary file 1: strain list. elife-42182-supp1.xlsx (12K) DOI:?10.7554/eLife.42182.033 Transparent reporting form. elife-42182-transrepform.pdf (869K) DOI:?10.7554/eLife.42182.034 Data Availability StatementAll data are included in the manuscript. Abstract The length of the mitotic spindle scales with cell size in a wide range of organisms during embryonic development. Interestingly, in embryos, this goes along with temporal Rabbit Polyclonal to DHX8 regulation: larger cells speed up spindle assembly and elongation. We demonstrate that, similarly in fission yeast, spindle length and spindle dynamics adjust to cell size, which allows to keep mitosis duration constant. Since prolongation of mitosis was shown to affect cell viability, this may resemble a mechanism to regulate mitosis duration. We further reveal how the velocity of spindle elongation is regulated: coupled to cell size, the amount of kinesin-6 Klp9 molecules increases, resulting in an acceleration of spindle elongation in anaphase B. In addition, the number of Klp9 binding sites to microtubules increases overproportionally to Klp9 molecules, suggesting that molecular crowding inversely correlates to cell size and might have an impact on spindle elongation velocity control. and various metazoans where cell size gradually decreases while the embryo undergoes successive rounds of cell division, spindle length can be reduced from 60 to a few micrometers (Crowder et al., 2015; Hara and Kimura, 2009; Whr et al., 2008). Also apart from embryogenesis, spindle length has been shown to adjust to cell size in and human cells (Rizk et al., 2014; Yang et al., 2016). This relationship is regulated by the cytoplasmic volume through limiting cytoplasmic components, such as tubulin (Good et al., 2013; Hazel et al., 2013), as well as by molecules modulating microtubule dynamics (Hara and Kimura, 2013; Lacroix et al., 2018; Reber and Goehring, 2015; Wilbur and Heald, 2013). In general, the regulation of the size of subcellular structures is considered crucial for many cellular processes, and especially for mitosis. For instance, mitotic spindle length order ZM-447439 can ensure proper chromosome segregation. In neuroblast mutant cells exhibiting abnormally long chromosome arms, cells elongate and form slightly longer spindles to exclude chromatid from the cleavage plane (Kotadia et al., 2012). Thus, in cells of different sizes the adjustment of spindle length might be critical to separate the two chromosome sets by an appropriate distance, avoiding that chromosomes intrude into the site of cell cleavage, which would result in chromosome cut (Syrovatkina and Tran, 2015). Interestingly, evidence exists that such a scaling relationship is not restricted to size but order ZM-447439 also applies to the speed of mitotic processes. In embryos, the velocity of spindle assembly in prophase and the velocity of spindle elongation in anaphase B adjust to cell size, such that longer spindles assemble and elongate with proportionally higher speeds (Hara and Kimura, 2009; Lacroix et al., 2018). This may prevent extension of mitosis duration in larger cells. In fact, prolongation of mitosis has often been shown to result in cell death or arrest in subsequent cell cycle phases (Araujo et al., 2016; Lanni and Jacks, 1998; Orth et al., 2012; Quignon et al., 2007; Rieder and Palazzo, 1992; Uetake and Sluder, 2010). Thus, the time frame needed for chromosome segregation has to be regulated to ensure flawless cell division. Still, it is not known how the scaling of spindle dynamics and cell size is established. Computer simulations suggest order ZM-447439 that the cell-size-dependent spindle elongation velocity in embryos depends on the number of cortical force-generators pulling on spindle poles (Hara and Kimura, 2009). In contrast to this mechanism of anaphase B, many other organisms push spindle poles apart via microtubule sliding forces generated between antiparallel overlapping microtubules?(MTs) at the spindle center (spindle midzone) (Brust-Mascher et al., 2004; Brust-Mascher and Scholey, 2011; Hayashi et al., 2007; Khodjakov et al., 2004; Toli?-N?rrelykke et al., 2004). In most organisms, these forces are generated by kinesin-5 (Avunie-Masala et al., 2011; Brust-Mascher et al., 2009; Kapitein et al., 2008; Kapitein et al., 2005;.