TransgenICSI reviewed: Foreign DNA transmission by intracytoplasmic sperm injection in rhesus monkey

This brief review considers the status of transgenesis by intracytoplasmic sperm injection (ICSI) with nonhuman primates. GFP expressing rhesus macaqu es embryos (mean = 34.6%; N = 81) were produced by ICSI using rhodamine-tag ged DNA encoding the green fluorescence protein (GFP) gene bound on sperm. Rhodamine signal was lost at the egg surface during in vitro fertilization (IVF) but could be traced by dynamic imaging during ICSI within the egg cyt oplasm. GFP gene was expressed as early as the 4-cell stage in ICSI embryos but not in embryos produced by in vitro fertilization (IVF). The percentag e of GFP expressing blastomeres increased during embryogenesis to the blast ocyst stage. Three offspring resulted from seven embryo transfers-a set of anatomically normal twins (a male and a female) stillborn 35 days premature , and a healthy male born at term. Although transgene was not detected in t he offspring, the successful production of live primates using DNA bound sp erm by ICSI suggests an alternative route to creating transgenic animals. I t also raises concern regarding transmission of infectious material during ICSI. (C) 2000 Wiley-Liss, Inc.