Fig. 5. Dorsocross interacts genetically with pnr and tin. (A-F) Presence of cardioblasts in the dorsal vessel of embryos with reduced copies of Doc, pnr and tin genes was examined in stage 16 embryos by anti-Mef2 (red) and anti-Doc2+3 (green) staining. For clarity, clearly identifiable regions of the Mef2-stained midgut lining were removed from the deepest sections prior to merging. (A) Wild type with two cardioblast rows along the dorsal midline. Doc is strongly expressed in the Svp-CBs. (B) Fewer cardioblasts, particularly of the Doc⁺ type, are seen in Df(3L)29A6/Df(3L)DocA transheterozygous embryos in which Doc1 is deleted and only one copy each of Doc2 and Doc3 is present. Bracket indicates cardioblasts within one abdominal segment. Even fewer cardioblasts are specified in Df(3L)29A6/Df(3L)DocA tin³⁶⁴ (C) and Df(3L)29A6/Df(3L)DocA pnr^VX6 (D) transheterozygous embryos, frequently leading to gaps in the cardioblast rows (arrows). (E) Cardioblast number is further reduced in Df(3L)29A6/Df(3L)DocA pnr^VX6 tin³⁶⁴ transheterozygous embryos and only short regions of the dorsal vessel are formed. (F) Embryos with one copy of tin, pnr and Doc1, and two copies of Doc2 and Doc3 [Df(3L)29A6/pnr^VX6 tin³⁶⁴] also have a reduced number of cardioblasts, but there is no bias towards loss of Doc⁺ cardioblasts as seen in in B-D. (G,H) Dorsal view of stage 16 embryo stained for Odd (green) and Srp (red) proteins. In the wild type (G), Odd labels Odd-pericardial cells (Odd-PC) and the lymph gland (LG). Srp co-localizes with Odd in the lymph gland, but is also expressed in other tissues, including the amnioserosa (as). In Df(3L)29A6/Df(3L)DocA pnr^VX6 tin³⁶⁴ transheterozygous embryos (H), only few Odd-pericardial and lymph gland cells are present.