Expression of α-actin and β-actin in embryonic zebrafish. One-day-old embryos were subjected to in situ hybridization using the α-actin (A and B) or β-actin (C and D) probe. A and C are whole mounts, while B and D are cross sections.

Transient expression of GFP in α-actin–GFP-injected embryos. Embryos were viewed through their chorions. S, M, W, and X are the expression levels of GFP in each embryo. S, strong; M, moderate; W, weak; X, very weak, so that the embryo should be discarded.

Expression of GFP in transgenic embryos generated using α-actin–GFP. Embryos were viewed through their chorions, except for (B) where chorions were removed. (A) 30-h-old embryos of a B-rank transgenic line. Nonfluorescent embryos are nontransgenic siblings. (B) 28-h-old embryos of C-rank and D-rank transgenic lines. A nontransgenic embryo is also shown. (C) 26-h-old embryos of an A-rank transgenic line. (D) A 13-h-old embryo of an A-rank transgenic line. (E) A 26-h-old embryo of the most fluorescent line (A-rank). Film-exposure time for this figure was much shorter than that in other figures. Due to the high fluorescence of the muscles, other regions of the embryo are clearly visible.

Expression of GFP in transgenic embryos generated using β-actin–GFP. Chorions were removed. Nonfluorescent embryos are nontransgenic siblings. (A) A typical transgenic embryo at 28 h. (B) A transgenic embryo from the most fluorescent line at 28 h.