Generation of transgenic quails by in vivo transfection of primordial germ cells

During development, dynamic changes in tissue shapes known as morphogenesis result from the exquisite orchestration of signalling pathways, cell cell interactions, cell divisions, and coordinated movements. How cells within embryos adopt a vast array of cell fates and tissue shapes in such an ever-changing environment has fascinated scientists for generations, yet the ability to observe and characterize those rapid changes has proven technically challenging in higher vertebrates. The japanese quail (Coturnix coturnix japonica) is an attractive model where basic rules driving morphogenesis in amniotes can be deciphered using genetic approaches. Similar to the more popular chicken model, the quail embryo is easily accessible to a wide range of manipulations and live imaging. A decisive asset of quail over chicken is a much shorter life cycle, which makes its use as genetic model for basic research extremely appealing. To date, all existing transgenic quail lines were generated using replication-deficient lentiviruses, but diverse limitations of this approach have hindered the widespread expansion of such technology. Here, we successfully used a plasmid-based in vivo transfection of quail primordial germ cells (PGCs) to generate a number of transgenic quail lines over a short period of time. The plasmid-based approach is simple, efficient and it allows using the infinite variety of genome engineering approaches developed in other models, such as strategies to facilitate transgenic bird selection, shown here. This major technological development completes the vast panel of techniques applicable to the avian model, making it one of the most versatile experimental systems available.