Pronuclear injection

Pronuclear injection Random, multiple copies in single integration site 1-100 (not controllable) Each founder is genetically unique Must breed multiple lines. Transgene expression and/or copy number may be unstable... 

Concentration of DNA for pronuclear injection plays a significant role in the viability of embryos. Usually, 1 to 2 pg/ml is the optimum concentration of DNA. This is equivalent to about 600 to 800 copies of a plasmid with a length of 5 kb. At lower concentrations, the frequency of integrations is also low, whereas at concentrations of 10 pg/ml or more, the survival rate of embryos is drastically reduced. 

Figure 4. Steps in the production of transgenic animals (pronuclear injection method).

Gordon, J. W., and Ruddle, F. H. (1983) Gene transfer into mouse embryos. Production of transgenic mice by pronuclear injection. In Methods in Enzymology (R. Wu, L. Gross-man, and K. Moldave, eds.), Vol. 101, pp. 411-433. Academic Press, San Diego. 

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