FIG. 1.
The MafA R1-6:eGFP and R1-6ΔR3:eGFP transgenes are expressed in similar tissue-specific manners. (A) Diagrams of the R3 (A), R1-6 (B), and R1-6ΔR3 (C) transgenic constructs. The start of transcription is from the hsp68 minimal heat shock promoter in R3:eGFP, while the endogenous start site in region 6 is utilized in the R1-6:eGFP and R1-6ΔR3:eGFP lines. Nuclear GFP was produced from all of the constructs (data not shown). (D) Whole-mount immunofluorescence of E13.5 embryos, performed with both R1-6:eGFP (E line is shown) and R1-6ΔR3:eGFP transgenic mouse lines. The expression patterns in these transgenic mouse lines were similar in most tissues, including the lens and limb buds (arrows), yet were absent in the spinal cord in R1-6ΔR3:eGFP mice (arrowhead). l, lens; d, digit tips; w, whisker hair shaft; h, hind limb; sc, spinal cord; BF, bright field; GFP, GFP fluorescence.