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Fig. 4
Transient transgenesis strategy for rapid evaluation of enhancer activity upon PhiC31-mediated targeting. (A) Schematic of PhiC31-targeted integration system, designed for cis-regulatory element analyses in transient transgenic embryos. ‘-2.4 shh’, 2.4 kb upstream region of shh gene; ‘shhABC’, shh complete introns 1 and 2, with ar-A, ar-B, ar-C enhancers (Müller et al., 1999; Ertzer et al., 2007). (B) Detection of reporter activity in embryos injected with construct containing the shh cis-regulatory elements by in situ hybridisation (B) and fluorescence microscopy (C). Arrows indicate activity in shh expression domains, resulting from successful integration of the shh cis-regulatory cassette in to the attP site of uobL12, whereas arrowheads indicate the activity of the crygc promoter in uobL12 recipient line. Scale bars: 150 μm.