Figure 8. A diagram showing gene regulation within the maf family and of other effector genes during lens development in the chick

The bold arrow indicates the order of expression for the three large maf genes in lens lineage. An early-expressed Maf positively regulates later-expressed members. Later-expressed MafB inhibits the expression of L-Maf and c-Maf. All three Maf proteins can activate several common genes such as δ-crystallin, cp49, cp95, Prox1 [6], (H.M.R. and K.Y., unpublished data), and MIP. On the other hand, distinct effects are also observed, as L-Maf induces Six3, Cx43, and Cx45.6; c-Maf upregulates Cx43, and MafB induces E-cadherin but downregulates Cx43. Hence, both redundant and distinct functions of L-Maf, c-Maf, and MafB essentially control many vital genes during lens development.