[Analysis of expression of the RSV-lacZ-gene in transgenic embryos of the loach Misgurnus fossilis L. during different variations of injection].

Several series of microinjection of the RSV-lacZ gene (the Escherichia coli beta-galactosidase gene under the control of the long terminal repeat of the Raus sarcoma virus) into fertilized mud loach eggs were carried out. The expression of the transgene in 3-5 day-old fry was shown to depend neither upon the stage of fry development at which the RSV-lacZ gene was introduced (early blastodisc, late blastodisc, 2-blastomere embryo) nor upon the region of transgene injection (blastodisc cytoplasm or egg yolk). Additionally, when injected into yolk, a smaller number of transgene expression points were observed and their distribution was confined to the surface of the yolk sac. In some experimental series, transgene expression was observed in 100% of embryos. The presence of exogenous genetic material in one of the experimental series was proved for 100% of 5- to 6-week old juveniles, when injected into cytoplasm, and for 67% of juveniles, when injected into yolk. This work provides evidence of the possibility of 100% transfer and expression of exogenous DNA when transgenic loachs are generated by injection into embryos and fry at different stages of their development.