Enhancement of reporter gene detection sensitivity by insertion of specific mini-peptide-coding sequences.

Two important aspects of gene therapy are to increase the level of gene expression and track the gene delivery site and expression, and a sensitive reporter gene may be one of the options for preclinical studies and possibly for human clinical trials. We report the novel concept of increasing the activity of the gene products. With the insertion of the mini-peptide-coding sequence CWDDWLC into the plasmid DNA of a SEAP reporter gene, we observed vast increases in the enzyme activity in vitro in all murine and human cell lines used. In addition, in vivo injection of this CWDDWLC-SEAP-encoding gene resulted in the same increases in reporter gene activity, but these increases did not correspond to alterations in the level of the gene products in the serum. Minor sequence changes in this mini-peptide negate the activity increase of the reporter gene. We report the novel concept of increasing the activity of gene products as another method to improve the reporting sensitivity of reporter genes. This improved reporter gene could complement any improved vector for maximizing the reporter sensitivity. Moreover, this strategy has the potential to be used to discover peptides that improve the activity of therapeutic genes.