Effect of short interspersed element sequences on the integration and expression of a reporter gene in the preimplantation-stage mouse embryos

Based on the assumption that foreign DNA sequences may have increased chanc e of integration into the host genome if they are flanked by high copy-numb ered genomic sequences such as SINEs (short interspersed elements), we inve stigated the integration frequency of Lac Z reporter gene flanked by a fuse d B1/B2 in an in vivo system using pronuclear microinjection technique in t he mouse. The SINE-flanked DNA showed a 4-fold increased integration freque ncy of the reporter gene than the control DNA (63% vs. 16%). Moreover, the level of beta-galactosidase expression, estimated from the X-Gal staining i ntensity in transgenic embryos, was greatly higher in SINE-carrying DNA. Th ese results suggest that the SINE sequences can serve a very useful tool in improving the efficiency of current transgenic animal technology. Mol. Rep rod. Dev. 56:366-371, 2000. (C) 2000 Wiley-Liss, Inc.