In an article published on September 5th in Biophysical Journal, the team of Associate Professor Kensuke Kawade at the Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology in Japan showed that a transcriptional co-activator ANGUSTIFOLIA3 (AN3) forms a signaling gradient along the leaf proximal-to-distal axis to determine cell-proliferation domain. In particular, by experimental and theoretical approaches, they demonstrated that pure diffusion in a growing tissue is sufficient to explain the AN3 gradient formation. This work provides evidence that the diffusion-based model of morphogen is viable in developmental patterning of multicellular organisms.

Morphogen gradient in a leaf primordium

AN3 expression is visualized by using green fluorescent protein, GFP. Long-range gradient of AN3 can be seen from base (left) to tip (right), which was achieved by a simple diffusion-based model in the growing leaf.