DCB Seminar Series: Jimmy Yilun Zhu

Seminar held in person only.

“Robust development of the Drosophila wing disc: the long and short of it”
Developing tissues use multiple mechanisms to create spatial patterns of cell differentiation. Morphogen gradients spread over hundreds of µm to convey long-range positional information, while local cell-cell interactions ensure short-range coordination. Focusing on the Drosophila larval wing imaginal disc, I will discuss two examples of how such mechanisms support development that is robust to disturbances. The first is the decapentaplegic (Dpp) morphogen gradient, which scales itself to changes in disc size. The second involves the phenomenon of “cell competition”, in which cells detect and eliminate neighbors that differ from themselves. In the first case, I will discuss how feedback loops involving the regulation of Dpp receptor and co-receptor expression enable automatic scaling—but only up to a certain size, suggesting that the need for robustness limits the sizes to which discs may grow. In the second case, I will present evidence that cell competition, despite being a short-range phenomenon, involves the active participation of hemocytes—macrophage-like cells recruited from outside the disc. These results highlight mechanistic parallels between the control of developmental patterning and adult phenomena such as tumor surveillance.