How are transgenic animals generated?
The cDNA encoding the therapeutic protein is optimized in silico and synthesized de novo prior to be combined with regulatory components from genes specifically expressed in milk. The construct is micro-injected into very early stage embryos which are then transferred to surrogate mothers. After one month (gestation time in rabbit) the first-generation offspring (F0 or genetic founders) is born. Young rabbits that have correctly integrated the transgene are identified by ear biopsy followed by PCR analysis. Founders are selected for their efficiency to produce the protein of interest in their milk and used to generate a second generation (F1) of transgenic rabbits. Transgenic F1 progeny is identified by ear biopsy followed by PCR analysis. Sexually mature F1 females are inseminated with non-transgenic sperm in order to obtain F2 progeny and milk. F1 females’ milk is mechanically collected and the recombinant protein of interest is characterized in order to select the best offspring lin
