Peafowl-chicken Interspecific Chimera

Green fluorescent protein gene-transfected peafowl somatic cells participate in the development of chicken embryos

This study was performed to investigate whether the embryonic somatic cells are capable of reconstituting and participating in the embryonic development of chickens to produce chimeras. In order to track the migration behavior of the donor cells, a cell line, originally isolated from an Indian peafowl embryo, was fluorescent-labeled by transfection of the cells with enhanced Green Fluorescent Protein (GFP) and Neomycin resistant (Neo) genes prior to injection into the stage X blastoderm of White Leghorn chickens. The injection was performed with a medium in the presence of 1-5% polyethylene glycol. The development of putative chimeric embryos between the stages three and 24 was examined for GFP expression under fluorescent light. To trace the peafowl cells in the developing chicken embryos, both a species-specific genetic marker originating from the mitochondrial DNA cytochrome b (cyt b) gene and a DNA fragment of GFP gene were used. Of the 185 fertile eggs manipulated, 173 developed into embryos. Fifty-five of them showed positive GFP patches in extra-embryonic tissues, and 15 expressed GFP in intra-embryonic tissues such as those of the head, heart, and gonad. PCR analysis revealed that PCR fragments for the peafowl mitochondrial DNA cyt b and GFP genes were detected in the samples of the GFP positive extra- and intra-embryonic tissues of the chimeras. The present results provide evidence that fluorescent-labeled peafowl embryonic cells carrying GFP and Neo genes are able to participate in the development of chicken embryos to generate chimeras.