Fig. 3

Fig. 3 Regulation of mCherry and CreER^T2 expression in the absence and presence of heat. A: Scheme of the Tg(hsp70l:mCherry-T2A-CreER^T2) construct, which expresses a single open reading frame coding for mCherry (red) and CreERT2 (yellow) separated by a viral T2A peptide sequence (green) under the control of a zebrafish heat shock–inducible hsp70l promoter (blue). After translation, the viral T2A peptide cleavage leads to the production of non-fused mCherry and CreER^T2 proteins. B: In the absence of heat, the Tg(hsp70l:mCherry-T2A-CreER^T2)^#12 allele is transcriptionally silent on CreER^T2 RNA and fluorescent mCherry level, respectively. C: In contrast, the Tg(hsp70l:mCherry-T2A-CreER^T2)^#15 enhancer trap allele is expressed in the forebrain (arrow), midbrain-hindbrain boundary (arrowhead), and rhombomere 4 of the hindbrain anlage (asterisk) at permissive temperatures. D: After heat shock, CreER^T2 RNA and fluorescent mCherry are expressed in a ubiquitous fashion. E: RT-PCR reaction analysis of the Tg(hsp70l:mCherry-T2A-CreER^T2) alleles. When the Tg(hsp70l:mCherry-T2A-CreER^T2) allele is provided maternally, Cre transcripts are detected for both alleles at the 2-cell stage and 24hpf. B–D: Dorsal and lateral views of transgenic embryos at the 12-somite stage and live 24-hpf embryos, respectively.