Numbers show the proportion of mouse lines expressing the transgene in the indicated sites. The construct 3 line described in detail in this work was line 6 (2 integrated DNA copies). Construct 3 line 5 (8 construct copies) gave very similar results. All other lines had approximately 1% (line 4, 20 copies), 2% (line 3, 9 copies), and 10% to 15% (lines 1 and 2, 8-10 copies) positive cells in the bone marrow. Values in fetal liver ranged between 0% and 2% (lines 4 and 3, respectively), 5% to 15% (lines 1 and 2), and 50% to 65% (lines 5 and 6). Results in gonads, AGM, and yolk sac are qualitatively similar to those presented for line 6, although some lines (3 and 4) gave weaker fluorescence. For construct 2, line 5 (12 construct copies) is described. Other examined lines were negative in fetal liver and bone marrow, but all lines (25 construct copies) were significantly fluorescent in the other regions examined. The construct 1 lines gave clear, but weak, fluorescence in gonads and AGM (line 4, 5 copies [Figure 6], and line 2, 8 copies). Line 4 also gave expression in allantoid. Ectopic expression was mainly in the central nervous system, after E11.5; it was detected in the 5 expressing construct 1 lines, in construct 2, line 4, and in construct 3, line 4.

Not all lines were examined in all sites. Other sites, possibly representing physiologic expression, were peripheral nerve ganglia, epidermis (melanocytes?), and heart