Method for identification of target genes of transcription factors

A method for the identification of a member that interacts with a transcription factor, said member selected from the group consisting of transcription factor responsive elements and target genes, said method comprising the steps of:

• (a) introducing a gene trap vector into an eukaryotic cell in culture, wherein the gene trap vector comprises the following elements in functional arrangement:
• a reporter gene,
• a polyadenylation site, and
• a selectable marker gene, thereby integrating said gene trap vector into the genome of said eukaryotic cell;
• (b) selecting cells containing said gene trap vector so integrated;
• (c) contacting said cells so selected with said transcription factor by adding said transcription factor to a cell culture medium of said cells so selected, wherein said transcription factor contains or is attached to a polypeptide comprising a third helix of a homeodomain capable of crossing the cell membrane and reaching the nucleus;
• (d) of the cells contacted in step (c), identifying and cultivating those having a target gene into which said gene trap vector has integrated and whose reporter gene activity has been altered as a result of the interaction of said transcription factor with a transcription factor responsive element of said target gene;
• (e) identifying said target gene;
• and
• (f) identifying the transcription factor responsive elements in the sequence adjacent to or within said target gene by detecting specific interaction between the transcription factor responsive elements and the transcription factor.