Figure 7
Expression of BfSim . (A-I) In situ hybridization of BfSim with antisense probe. (A,B) Early stages show no expression. (C) BfSim is expressed in a broad band of mesendodermal cells in the early neurula. (D,E) In mid-neurula (six somites), expression is localized to three areas: the pharynx roof, the posterior mesendoderm (arrowheads), and a patch of cells in the future cerebral vesicle (arrows). (F,G) In the late neurula (≥nine somites), the expression in cerebral vesicle is maintained, and BfSim expression was discovered in six clusters of cells, which are paired, within the central nervous system (CNS) (open arrowheads). (H,I) In larvae, the expression is maintained in the CNS cells, while the expression in the mesendodermal areas fades. (J-M) Double-fluorescent in situ hybridization images show the co-localization of BfSim and BfArnt. (J) In the early neurula, BfArnt is expressed ubiquitously, but BfSim expression is localized to dorsal mesendoderm. (K) In the mid-neurula, the BfSim-expressing cells in the CNS co-localize with the BfArnt expression (arrows); arrowheads show mesendodermal BfSim expression. (L,M) In the late neurula, the expression in CNS cells is maintained (arrows), and BfSim and BfArnt are co-expressed in six clusters of cells (open arrowheads). (N) The six clusters expressing BfSim also express the pan-neural marker AmphiElav/Hu (open arrowheads). The scale bar in A applies to panels A-I. Blastoporal views (bp) and dorsal views (d or Dorsal) are labeled, and other panels are lateral views. In C-G and J-N, anterior is to the left; in H and I, anterior is to the upper left.