The proliferation and differentiation programs are only partially coupled during C. elegans intestine development

Cell proliferation and differentiation are essential processes underlying multicellular organism development. Cell proliferation arrest usually precedes terminal differentiation, suggesting that these two processes may be coordinated. Here we took advantage of the very stereotyped development of the C. elegans intestine to address whether the control of the proliferation and differentiation programs are systematically coupled. We show that retarding cell cycle arrest leads to a delay in the recruitment of some, but not all, brush border components. Reciprocally, we find that cell cycle arrest relies on the differentiation factors ELT-2 and ELT-7 only in posterior intestinal cells. The occurrence of supernumerary divisions in the absence of ELT-2 and ELT-7 is associated with changes in the expression pattern of the cell cycle regulators CKI-1 and cyclin B1. Our work thus demonstrates the existence of reciprocal interactions between cell proliferation and cell differentiation. It nevertheless also shows that these two processes are only partially coupled, suggesting the existence of additional mechanisms ensuring their temporal control.