Fig. 4

Comparison of GFP expression patterns between heat shock treated and untreated hsp27-gfp embryos. (A,C) Ventral view of 96 hpf control untreated hsp27-gfp embryos at two different focus planes. (B,D) Ventral view of 96 hpf heat shocked hsp27-gfp embryos (treated at 72 hpf) at two different focus planes. GFP was induced strongly in pharyngeal muscles (B) and heart (D) after heat shock treatment as compared to control embryos (A, C). (E,F) 8 dpf hsp27-gfp embryos with (F) or without (E) heat shock treatment at 7 dpf. Note strong induction of GFP expression in the lens (F). (G–L) Sagittal sections of 48 hpf control (G) and heat shocked hsp27-gfp embryos (H–L). Heat shock was carried at 24 hpf for 2 h and the embryos were fixed for sectioning at 48 hpf. Only very weak GFP expression was found in skin of untreated embryos (G) and heat shock induced precocious GFP expression in the heart and somatic muscle as well as stronger GFP expression in skin (H). Induced GFP was also observed in the notochord (I), central nervous system including neurons in the brain (I) and spinal cord (J), and lens (K). Panels J and K are larger magnification of the framed region from (I). (M,N) GFP expression in the adult heart with (N) or without (M) heat shock. Strong GFP expression was observed only in the ventricle of both control (M) and heat shocked fish (N). Weak expression was observed in the atrium while no expression was observed in the bulbus arteriosus. O: Section of heart from a heat shock treated hsp27-gfp fish confirming that GFP is expressed strongly in the ventricle of heart. Abbreviation: A, atrium; BA, bulbus arteriosus; h, heart; hh, hyohyoideus; ih, interhyal; ima, intermadibularis anterior; imp, intermendibularis posterior; le, lens; sh, sternohyoideus; sk, skin; som, somites; V, ventricle. The nomenclature for cranial skeletal muscles is based on Schilling and Kimmel (1997). Scale bar for A–L: 100 μm. Scale bar for M–O: 1 mm.