Figure 6.

Co-localization of hairy1, sap18and sin3a mRNA expression in the prospective somitic territory and somites. (A) Whole mount in situ hybridization with the probe indicated on top was performed in chick embryos in somitogenesis developmental stages (upper panel). The lower panel is an amplified view of the rostral PSM and somites. Prior to in situ hybridization processing, a slit was made on the right side of the embryo (arrow), in the boundary between the last formed somite and the rostral PSM, evidencing the prospective somitic territory (bracket). (B) Schematic representation of the genes' expression domains, indicating (with an asterisk) the prospective somite and caudal region of already formed somites, where hairy1, sap18 and sin3a mRNA expression co-localize. Cyclic expression of hairy1 with a 90 minute periodicity is indicated.