Abstract: To explore the possible reasons for high mortality rate and early abnormal development of transgenic cloned pigs, we used anti-diarrhea transgenic (α1-fucosyl transferase gene, FUT1) positive and negative cloned pigs, as well as normal piglets as control, to analyze the expression levels of the imprinted gene insulin-like growth factor 2 (IGF2) in spleen, liver and leg muscle tissues via fluorescence quantitative RT-PCR assay. The results showed that in all three groups of pigs, there were differential expressions of IGF2 among tissues, expression level in liver tissue being the highest and that in the leg muscles being the lowest. Significant test indicated that the expression level of IGF2 in spleen tissue of FUT1 transgenic positive cloned pigs was significantly higher than that in negative cloned pigs (P<0.05), while it was significantly lower than that of negative cloned pigs in leg muscle tissue (P<0.05). Furthermore, the expression level of IGF2 in spleen of FUT1 transgenic negative cloned pigs was very significantly lower than that of normal pigs (P<0.01);However, it was very significantly higher than that of normal pigs in liver tissue (P<0.01). These results implied that the abnormal expression level of IGF2 in cloned pigs might influence their weak viability, however, its relationship with reduced survival rate of transgenic FUT1 gene cloned pigs was still needed to be defined.

Key words: transgenic FUT1 gene cloned pig; anti-diarrhea; imprinting gene IGF2; expression differences