FIGURE 8

Illustration of contributions of maternal eomesa, hwa/β-catenin signaling and Nodal signaling to ndr1 and ndr2 expression. The expression pattern of ndr1 and ndr2 in the late blastula (in lateral view with dorsal to the right and animal pole to the top) is depicted. The overall expression level of ndr1 or ndr2 is the sum of contributions from maternal eomesa (as seen in Mhwa without Nodal signaling), maternal hwa/β-catenin signaling (as seen in Meomesa without Nodal signaling) in and Nodal signaling (autoregulation). In wildtype (WT) embryos, all of the three forces make a significant contribution to ndr1 expression; however, maternal eomesa makes a predominant contribution to ndr2 expression while maternal hwa/β-catenin signaling may contribute a little to ndr2 expression by activating ndr1 in the dorsal blastodermal margin and thereof Nodal signaling. In the last column, ndr1 and ndr2 levels contributed by eomesa and hwa were shown as empty to highlight the contribution of Nodal signaling.