A systematic genomic screen implicates nucleocytoplasmic transport and membrane growth in nuclear size control

How cells control the overall size and growth of membrane-bound organelles is an important unanswered question of cell biology. fission yeast cells maintain a nuclear size proportional to cellular size,resulting in a constant ratio between nuclear and cellular volumes (n/c ratio). we have conducted a genome-wide visual screen of a fission yeast gene deletion collection for viable mutants altered in their n/c ratio,and have found that defects in both nucleocytoplasmic mrna transport and lipid synthesis alter the n/c ratio. perturbing nuclear mrna export results in accumulation of both mrna and protein within the nucleus,and leads to an increase in the n/c ratio which is dependent on new membrane synthesis. disruption of lipid synthesis dysregulates nuclear membrane growth and results in an enlarged n/c ratio. we propose that both properly regulated nucleocytoplasmic transport and nuclear membrane growth are central to the control of nuclear growth and size. © 2017 kume et al.