Fig. 2. lozenge in crystal cell formation.

serpent-positive (srp+) prohemocytes differentiate into gcm+/gcm2+ differentiating prohemocytes or lz+ immature crystal cells. Differentiation of prohemocytes into immature crystal cells is mediated by the Notch/Serrate interaction and moderated by u-shaped. Additionally, yki and sd control the crystal cell specification in a Notch/Serrate-dependent manner. High gcm/gcm2 expression reduces the number of crystal cells, however, fated crystal cells are inhibited by klu from becoming plasmatocytes. This high gcm/gcm2 cells become plasmatocytes. Increased lz in immature crystal cells coupled with hnt/peb, DnaJ-1, Mlf and Notch leads to formation of mature crystal cells which possess crystalline inclusions and express PPO1 and PPO2. The process of mature crystal cell formation is heavily dependent on lozenge expression from the onset to the late stage. The medullary, intermediate, and cortical zones demarcate three regions of the primary lymph gland lobe. Healthy animals do not actively generate lamellocytes. Though, prohemocyte tion is lamellocyte-biased upon immune challenges.