Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794-5222, USA.
Department of Functional Organization of Biomembranes, Institute of Experimental Medicine of the Czech Academy of Sciences, Videnska 1083, Prague 142 20, Czech Republic.
Mol Cell. 2020 Apr 16;78(2):359-370.e6. doi: 10.1016/j.molcel.2020.03.012. Epub 2020 Apr 3.
Yeast cells must grow to a critical size before committing to division. It is unknown how size is measured. We find that as cells grow, mRNAs for some cell-cycle activators scale faster than size, increasing in concentration, while mRNAs for some inhibitors scale slower than size, decreasing in concentration. Size-scaled gene expression could cause an increasing ratio of activators to inhibitors with size, triggering cell-cycle entry. Consistent with this, expression of the CLN2 activator from the promoter of the WHI5 inhibitor, or vice versa, interfered with cell size homeostasis, yielding a broader distribution of cell sizes. We suggest that size homeostasis comes from differential scaling of gene expression with size. Differential regulation of gene expression as a function of cell size could affect many cellular processes.
酵母细胞在分裂前必须生长到临界大小。目前尚不清楚如何测量大小。我们发现，随着细胞的生长，一些细胞周期激活物的 mRNA 比大小增长得更快，浓度增加，而一些抑制剂的 mRNA 比大小增长得更慢，浓度降低。大小比例的基因表达可能会导致激活物与抑制剂的比例随着大小的增加而增加，从而触发细胞周期进入。与此一致的是，CLN2 激活物从 WHI5 抑制剂的启动子表达，或者反之亦然，干扰细胞大小的动态平衡，导致细胞大小分布更广。我们认为，大小的动态平衡来自于基因表达与大小的差异比例。作为细胞大小的函数，基因表达的差异调节可能会影响许多细胞过程。
