Abstract
Cell proliferation and differentiation occur in spatially distinct regions of the same leaf primordia. A defect in cell proliferation in a leaf primordium often triggers enhanced cell expansion. This phenomenon is called compensation. Compensation strongly suggests the existence of a system coordinating these two cellular processes. So far, we showed that compensation induced by the overexpression of a cyclin-dependent kinase inhibitor, KRP2, occurred in a cell-autonomous manner by using a heat-shock-inducible Cre/Lox system. Then, is this a common property of the coordination system?
To answer this question, genetic chimeric leaves for AN3 expression were generated. In these chimeric leaves, even AN3 overexpressing cells showed compensation in the presence of an3 cells. The size of AN3-overexpressing cells was comparable to that of an3 cells. This fact indicated that compensation induced by an3 mutation is mediated by cell-to-cell communication. Thus, there are two qualitatively distinct systems linking cell proliferation and differentiation in cell-autonomous manner as seen in KRP2 overexpressor and non-cell-autonomous manner in an3 mutant.
