Effect of Cis-Located Human Satellite DNA on Electroporation Efficiency

The introduction of exogenous DNA into mammalian cells can ultimately result in the integration of the transfected DNA into the host genome (1 ,2 ). Any genes containing appropriate expression signals will, in most cases, be expressed both prior to and after integration. However, stable expression of the transfected genes is not always observed (3 ,4 ). One reason this is believed to occur is because the site of integration of the foreign DNA is virtually random with respect to both the exogenous DNA and the particular human chromosome (5 ). Therefore, it can be expected that not only the expression, but also the stability and copy number of the transfected gene will depend on the integration sites and chromosomal flanking sequences.