Systemic diffusion including germ cells after plasmidic in utero gene transfer in the rat.
OBJECTIVE
The integration of a proviral plasmid into the host genome could be a good approach for fetal somatic gene transfer. The goal of this study was to assess the integration and transcription of a proviral marker gene injected intraperitoneally into rat fetuses as well as the risks of maternal contamination and germ-line transmission.


METHODS
On day 17 post-coitus, each fetus was injected intraperitoneally with 10 microg plasmid DNA through the uterine wall. Twenty-one days after spontaneous delivery, integration and transcription of the plasmid in gonad, gut, liver, spleen, lung and brain tissue from 10 pups were determined by PCR and RT-PCR.


RESULTS
14 of 60 organs exhibited integration of the plasmid. Four samples of gut (40%), 3 samples of liver and spleen (30%), 2 samples of brain (20%) and no sample of lung were transfected. Two testicular samples were transfected and study of F1 rats from 2 brothers of one of the positive rats revealed transgenic pups from 1 of these 2 animals. No transfection of maternal tissues was detected.


CONCLUSIONS
Integration and transcription of a marker gene injected intraperitoneally into rat fetuses appear efficient, especially in intraperitoneal organs. The risk of maternal contamination appears very low when using a naked DNA plasmid injected directly into fetuses. However, germ-line contamination can occasionally occur even with injection late during pregnancy, suggesting further studies are necessary to assess this risk in direct gene transfer experiments.
Gallot
D
D
Laboratoire d'Oncologie moléculaire, Centre Jean-Perrin, Clermont-Ferrand, France. dlemery@chu-clermontferrand.fr
Seifer
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I
Lemery
D
D
Bignon
Y J
YJ
D000818:Animals; D001923:Brain Chemistry; D004247:DNA / Q000032:analysis; D004058:Diffusion; D005260:Female; D005315:Fetal Diseases / Q000628:therapy*; D018390:Gene Targeting; D018014:Gene Transfer Techniques; D005819:Genetic Markers; D015316:Genetic Therapy / Q000379:methods*; D007274:Injections, Intraperitoneal; D007422:Intestines / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D008168:Lung / Q000737:chemistry; D008297:Male; D010053:Ovary / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D051381:Rats; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000737:chemistry; D013737:Testis / Q000737:chemistry; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics
D005819:Genetic Markers; D004247:DNA; D001616:beta-Galactosidase