Reporter transposon and potential routes of inter-fetal and feto-maternal cell trafficking in the pig.

<p>A) Schematic depiction of a monomeric reporter transposon in chromosomal context. The SB transposon consists of <i>CAGGS</i> promoter, <i>Venus</i> cDNA and polyadenylation sequence flanked by SB inverted terminal repeats (ITRs). Drawing not at scale. B) Fetal cells might traffic directly between fetuses (I.) or via the maternal circulation (II.). In both cases the non-transgenic fetuses should carry Venus-expressing cells. In case (II.), the mother should also show cell chimerism. For simplification only two fetuses are depicted and only the transgenic fetus is shown in green, however, cells of amnion and allantois are also Venus positive. C) Specific Venus fluorescence in embryonic allantois at day 25 of gestation. Cryosection of a <i>CAGGS-Venus</i> transgenic implantation in a wild-type sow. D) Overlay of fluorescence and brightfield views. E) Corresponding brightfield view. A dotted line indicates the border between embryonic and maternal tissue. Bar = 10 µm.