ANALYSIS OF RSV-LACZ GENE-EXPRESSION IN T RANSGENIC EMBRYOS OF MUD LEECH MISGURNUS-FOSSILIS L WITH DIFFERENT VARIANTS OF INJECTION

Several series of microinjection of the RSV-lacZ gene (the Esherichia coil beta-galactosidase gene under the control of the long terminal re peat of the Raus sarcoma virus) into fertilized mud leach eggs were ca rried out. The expression of the transgene in 3 - 5 day-old fry was sh own to depend neither upon the stage of fry development at which the R SV-lacZ gene was introduced (early blastodisc, late blastodisc, 2-blas tomere embryo) nor upon the region df transgene injection (blastodisc cytoplasm or egg yolk). Additionally, when injected into yolk, a small er number of transgene expression points were observed and their distr ibution was confined to the surface of the yolk sac. In some experimen tal series, transgene expression was observed in 100% of embryos. The presence of exogenous genetic material in one of the experimental seri es was proved for 100% of 5- to 6-week old juveniles, when injected in to cytoplasm, and for 67% of juveniles, when injected into yolk. This work provides evidence of the possibility of 100% transfer and express ion of exogenous DNA when transgenic loachs are generated by injection into embryos and fry at different stages of their development.