G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139.
Proc Natl Acad Sci U S A. 2013 Oct 8;110(41):16687-92. doi: 10.1073/pnas.1315290110. Epub 2013 Sep 24.
The coupling of the rate of cell growth to the rate of cell division determines cell size, a defining characteristic that is central to cell function and, ultimately, to tissue architecture. The physiology of size homeostasis has fascinated generations of biologists, but the mechanism, challenged by experimental limitations, remains largely unknown. In this paper, we propose a unique optical method that can measure the dry mass of thick live cells as accurately as that for thin cells with high computational efficiency. With this technique, we quantify, with unprecedented accuracy, the asymmetry of division in lymphoblasts and epithelial cells. We can then use the Collins-Richmond model of conservation to compute the relationship between growth rate and cell mass. In attached epithelial cells, we find that due to the asymmetry in cell division and size-dependent growth rate, there is active regulation of cell size. Thus, like nonadherent cells, size homeostasis requires feedback control.
细胞生长速度与细胞分裂速度的耦合决定了细胞大小，这是细胞功能的一个决定性特征，最终决定了组织的结构。大小稳态的生理学激发了几代生物学家的兴趣，但由于实验限制的挑战，其机制在很大程度上仍然未知。在本文中，我们提出了一种独特的光学方法，该方法可以以高计算效率准确测量厚活细胞的干质量，就像薄细胞一样。使用该技术，我们以前所未有的精度量化了淋巴母细胞和上皮细胞分裂的不对称性。然后，我们可以使用 Collins-Richmond 守恒模型来计算生长速率和细胞质量之间的关系。在附着的上皮细胞中，我们发现由于细胞分裂和尺寸依赖性生长速率的不对称性，细胞大小受到主动调节。因此，与非附着细胞一样，大小稳态需要反馈控制。
