Origins of licensing control

摘要

Organ development requires precise regulation of both the total number and the different types of cells. Much is known about how each process is controlled, but new light has been shed on how the two are linked. From fertilization to maturity, a single set of genetic information must be accurately passed on to each daughter cell during the cell cycle; the mechanism involved is known as 'replication licensing'. At the same time, specialized cells and organs use unique combinations of genes, which are switched on or off by factors that control gene transcription, and this process - cell differentiation - determines the types of cell that will arise. These two processes are expected to be tightly integrated during development in order to generate organs of the correct size. On pages 745 and 749 of this issue, Wittbrodt et al. and Kessel et al. provide further insights into the molecular interactions between regulation of the cell cycle and regulation of cellular differentiation.