Exploring transgene transfer from the transgenic chicken model to its offspring through a nonviral vector

There is much interest in using chickens as "bioreactors" to produce large quantities of biopharmaceuticals. However, transient expression of foreign genes have been known to cause low efficiency of obtaining transgenic offspring, especially when using nonviral vectors. In present study, a transgenic chicken model was investigated to determine whether an exogenous gene can be expressed stably and transferred to its offspring through a matrix attachment region (MAR)-mediated non-viral vector using the eGFP marker gene. The eukaryotic expression vector pEGFP-N1-MAR, which contains the eGFP gene and MAR, was constructed and transfected into a chicken stage-X blastoderm to produce a G0 generation of transgenic chickens. The hatchabilities of different injection regions were tested; 18 of the 40 eggs injected with pEGFPN1- MAR in the area opaca hatched after 21 days of incubation, and had a hatchability rate of 45%. By contrast, eggs injected at the area pellucida did not hatch. Results from the fluorescence signal detection and polymerase chain reaction (PCR) verified that four hatched chicks from the G0 generation expressed the eGFP gene. Furthermore, fluorescence signal detection results indicated that 2 of the 65 chicks from the G1 generation expressed the eGFP gene. We conclude that MAR facilitates the production of transgenic chickens; pEGFP-N1-MAR application is a novel approach that can produce transgenic chicken offspring.