Figure 11. Summary diagram depicting the structural remodeling of gap junctions during fiber cell differentiation and maturation in the adult chicken lens. Stage 1: Formation of small, irregular gap junctions with a few loosely-packed connexons in superficial cortical fiber cells. Stage 2: Growth of a large gap junction with numerous loosely-packed connexons in the young outer cortical fiber cells. Stage 3: Early stage of gap junction remodeling begins in the deeper regions of the outer cortex, displaying several small clusters of crystalline-packed connexons intermingled with a majority of loosely-packed connexons. Stage 4: Mature stage of gap junction remodeling exhibiting distinct hexagonal crystalline-packed connexons observed mainly in the mature inner cortical fiber cells. Due to the compaction of these connexons, these crystalline gap junctions are mostly smaller in size. In concert with these changes, the gap junctions in Stages 1 and 2 are cholesterol-rich, in Stage 3 are cholesterol-intermediate, and in Stage 4 are cholesterol-free. Furthermore, the COOH-terminus of Cx50 is apparently lost in the gap junctions with crystalline-packed connexons in Stage 4.