[Expression of the CMV-lacZ- and RSV-lacZ-genes in transgenic fish and mouse embryos]

The bacterial gene for beta-galactosidase under the control of LTR from either human cytomegalovirus (CMV-lacZ) or the Rous sarcoma virus (RSV-lacZ) was injected into fertilized eggs of Misgurnus fossilis L. loaches and F1 hybrid mice (CBA x C57Bl). Expression of the CMV-lacZ was observed in almost 100% of the loach embryos and larvae for two months following the first day of embryonic development. In some cases, expression points were located only on either the right or the left side of a fish. The spectrum of tissues expressing CMV-lacZ was decreased during embryonic development: CMV-lacZ was expressed only in fin and body muscles of 6- to 8-week-old loaches. In mice, the RSV-lacZ gene was expressed in ectoderm- and mesoderm-derived tissues of a 13-day-old embryo, and the CMV-lacZ gene was expressed in tissues derived from various blastophylli of a 14-day-old embryo. Distribution of transgene expression is discussed with regard to authors' and published data.