Figure 4. Segregation of Venus-transposons in F1-fetuses.

Fetuses derived from insemination of a wildtype sow with semen of transgenic boar #503 were isolated at day 29 p.c., and fluorescence images were taken under normalized conditions. A) Typical image of a strongly fluorescent fetus (F1-2), B) Typical image of a weakly fluorescent fetus (F1-4). The fluorescence intensities correlated with the transposon copy numbers, as determined by Southern blotting. C) Flow cytometric measurements of Venus-fluorescence in fibroblasts derived from F1-fetuses with weak fluorescence intensity: F1-1 (red), F1-5 (purple), F1-11 (yellow) and strongly fluorescent fetuses: F1-5 (blue) and F1-9 (green). D) Expression of Venus in different tissues of d29 porcine fetus (F1-3, strongly fluorescent) as determined by Northern blotting with a Venus-specific probe (top): head (1); carcasse (2); mesonephros (3); liver (4); heart/lung (5) and control samples from wildtype pig: heart (6); lung (7); liver (8). In addition, RNAs from wildtype murine heart (9) and lung (10); and RNAs from Venus-transposon transgenic murine heart (11) and lung (12) were loaded. Bottom, reprobed blot with an actin-specific probe. Porcine tissues show organ-specific splice patterns of actin transcripts [51]. E) Segregation of Venus-transposons in F1-animals. Genomic DNA from F1-fetuses was analysed by Southern blot with the Venus-probe. M, size marker; 1–10, genomic DNA from ten F1 offspring. Black arrow, internal, constant band at ∼1.4 kb; blue arrow, external fragment of one integrant; red arrow, external fragment of the other integrant. 1× and 2× indicate the deduced transposon copy numbers.