Hens that lay transgenic eggs could both greatly facilitate the study of embryonic development and provide bioreactors for the pharmaceutical industry;however, generating them has proved technically difficult. Chapman and colleagues have now cracked this challenge to produce homozygous roosters and hens that ubiquitously express enhanced green fluorescent proteins (eGFP; see ). By injecting a replication-defective lentiviral vector expressing eGFP under the control of the phosphoglycerol kinase promoter into fertilised eggs, the researchers managed to create a rooster that carried the transgene in his germline. From this starting point, the authors then bred homozygous individuals that expressed eGFP uniformly throughout their tissues, which could be detected by in situ hybridization and immunocytochemistry. This paper thus shows that ubiquitous transgene expression is achievable in chickens and opens the way to deriving other transgenic chickens for use in developmental studies.
