Influence of the DNA amount per microinjection on the development and EGFP expression in bovine embryos

Abstract. Development and fluorescence expression were evaluated in bovine embryos microinjected with ~2 pl of DNA-buffer solution containing [I] 1.6, [II] 4.8 or [III] 8.0 ng/μl of the enhanced green fluorescent protein (EGFP) gene, respectively. The percentages of embryo cleavage and development to blastocysts for the DNA-injected groups (Groups I, II and III) were significantly (p < 0.05) lower than those in the centrifuged control group. However, no significant difference was observed among the DNA-injected and buffer-injected control groups with respect to the percentage of development to blastocysts. There was no significant difference among the DNA injected groups with respect to the percentage of total fluorescing embryos. However, the percentage of total embryos that fluoresced in all the cells (nonmosaic) was significantly (p<0.01) higher in Groups II and III than in Group I. These results using the EGFP maker indicate that nonmosaic expression of fluorescence in the microinjected embryos increased by increasing the DNA amount injected. However, those injected embryos exhibited impaired development irrespective of the DNA dose.