To examine the transfection of exogenous genes into chick embryos, applying the characteristics of avian leukosis virus (ALV)-induced chicken B cell line DT40 to the production of chimeric birds. Methods: The DT40cells incorporated with exogenous gene (lacZ constructs encoding Escherichia coli β-galactosidase: β-gal) were introduced into chick embryos by the injection of cells into stage X blastoderm. Manipulated eggs were incubated for 3 (trial 1 ) or 6 (trial 2) days, and the expression of lacZ DNA was detected by a histochemical staining method of β-galactosidase and polymerase chain reaction (PCR) analysis. Results: The survival rates of the manipulated embryos incubated for 3 days (stage 18-20: trial 1) and 6 days (stage 28, 30: trial 2) were about 42% and 38%, respectively.The expression rates of the lacZ gene in the embryos in the trials 1 and 2 were about 60% and 23%, respectively, for the survived embryos. Conclusio: The rate of embryonic viability and expression rate of introduced genes were not so high, but it suggested the possibility of utilizing the DT40 cells as a vector for carrying exogenous genes into chick embryos.

AIMTo confirm the stability of exogenous genes in the generation of transgenic chickens using ejaculated chicken sperm, the deoxyribonuclease (DNase) activity was evaluated in the seminal plasma of ejaculated semen and the stability of DNA was examined by adding lipofection reagents.

METHODSA PCR fragment (249 bp) of pEGFPN-1 vector was used as the DNA substrate and was incubated with the seminal plasma at 40 degree C for 30 min. Then, the whole reaction solution was subjected to agarose gel electrophoresis and the DNA size was evaluated under UV light.

RESULTSThe DNA substrate was completely diminished after incubation with seminal plasma. However, the substrate was intact after incubation with heat-treated seminal plasma or incubation with seminal plasma in the presence of 0.5 mmol/L approximately 5 mmol/L EDTA. The substrate was stabilized in the seminal plasma by the addition of commercially available lipofection reagents.

CONCLUSIONThe DNase activity is present in the seminal plasma of ejaculated chicken semen. However, DNA is stable in the liposomal-DNA complex.

Animals ; Cations, Divalent ; pharmacology ; Chickens ; physiology ; DNA ; analysis ; DNA Primers ; Deoxyribonucleases ; analysis ; Edetic Acid ; pharmacology ; Hot Temperature ; Indicators and Reagents ; Male ; Reverse Transcriptase Polymerase Chain Reaction ; Semen ; enzymology