Fig. 2.

Expression of chick myocardin transcripts in chick embryos. Whole mount in situ hybridization was used to detect the expression of chick myocardin transcripts in staged chick embryos during early developmental stages. Myocardin expression was first detected in the cardiac crescent (cc) of Hamburger-Hamilton (HH) Stage 9 chick embryos (A). Myocardin is expressed in the newly formed heart tube (h) of HH Stage 10 and 11 embryos (B and C). Higher level of myocardin expression was detected in the future atrium (a) of HH Stage 11 embryo (D). Myocardin expression is restricted to the cardiac lineage in HH Stage 12–13 chick embryos (E–H). Arrows indicate higher level of myocardin expression detected in the atrium (a) and outflow tract (ot). Myocardin expression in the hearts of HH Stage 15 chick embryos (I–L). Arrows indicate higher level of myocardin expression in the atrium (a) and outflow tract (ot). Myocardin expression in HH Stage 18 chick embryos (M–P). Arrows indicate higher level of myocardin expression detected in the atrium (a) and outflow tract (ot). Myocardin is expressed in the developing heart (h) and allantoic vesicle (all) of HH Stage 21 chick embryos (Q–T). Images in 2D, J, L, N, P, R, and T represent higher magnification of 2C, I, K, M, O, Q, and S, respectively. Abbreviations: a, atrium; all, allantoic vesicle; cc, cardiac crescent; h, heart; lv, left ventricle; ot, outflow tract; rv, right ventricle; v, ventricle.