National Avian Research Facility
National Avian Research Facility


Inducible expression of eGFP by CRE-mediated recombination

Summary & Utility

The Lox-STOP-lox chicken line is a powerful tool for developmental biology, facilitating fate mapping and cell lineage tracing. The Lox-STOP-lox line carries a transgene in which the expression of eGFP from a ubiquitous promoter is initiated after CRE-recombinase-mediated recombination, either by Cre protein application, by application of a Cre-expressing plasmid1 or by crossing birds with this transgene to a second line which expresses CRE. After induction of expression of eGFP by recombination, all descendant cells express eGFP. This allows cells or specific cell populations to be marked and tracked during embryonic development.


Line origin

The Lox-STOP-lox line is a relatively recent addition to our reporter lines, generated at the Roslin Institute and mentioned in Davey et al. (2018)1, publication in preparation. The Lox-STOP-lox line was made by generating a HIV lentiviral vector in which the ubiquitous enhancer/promoter CAGGS2 is separated by the lox-stop-lox sequence from eGFP. The loxP>>-dSTOP-loxP> sequence  was isolated from plasmid pJFRC172-10XUAS-loxP>-dSTOP-loxP>-myr::GFP (a gift from Gerald Rubin (Addgene plasmid # 32145)3, and the CAGGS-lox-stop-lox-eGFP sequence was inserted in reverse orientation in the vector. The original funding to establish this line was provided by the Wellcome Trust.


To reference this line for publications please contact Professor Helen Sang.



  1. Davey, M. G., Balic, A., Rainger, J., Sang, H. M. & McGrew, M. J. Illuminating the chicken model through genetic modification. Int. J. Dev. Biol. 62, 257–264 (2018).
  2. Niwa, H., Yamamura, K. & Miyazaki, J. Efficient selection for high-expression transfectants with a novel eukaryotic vector. Gene 108, 193–199 (1991).
  3. Nern, A., Pfeiffer, B. D., Svoboda, K. & Rubin, G. M. Multiple new site-specific recombinases for use in manipulating animal genomes. Proc. Natl. Acad. Sci. U. S. A. 108, 14198–14203 (2011).