Size regulation requires both extrinsic and intrinsic mechanisms that define growth limits. Extrinsic mechanisms sense nutrient availability and control growth systemically. In contrast, intrinsic mechanisms regulate growth in individual organs and tissues in an autonomous manner. It has been postulated that one way intrinsic size regulation of organs is achieved is through organ compartmentalization.
The aim of this proposal is to investigate how developmental compartments contribute to organ growth and size. Expression of dMyc in the Posterior (P) compartment of the imaginal disc results in a proportionately normal size wing. We have found that cell death is increased within the P compartment, and also non-autonomously, in the Anterior (A) compartment in this case which might account for the proper size regulation. I propose studies to examine the role of cell death in regulation of the size of each compartment, and of the entire developing wing. Our results point to a possible asymmetry in growth regulation imposed by compartments. I propose experiments to address whether asymmetry exists and the possible mechanisms involved in this potential asymmetry. ? ? ?
