DNA sequences comprising gene transcription regulatory qualities and methods for detecting and using such DNA sequences

摘要

An isolated and/or recombinant DNA sequence having gene transcription modulating quality, wherein said sequence comprises a sequence having gene transcription modulating quality as determined by a process comprising the steps of: (a) growing cells in the presence of 250 g/ml zeocin and 0.1 ng/ml doxycycline for 5 weeks; (b) selecting colonies that still grow after 5 weeks; (c) verifying the presence of the DNA sequence having gene transcription modulating quality in plasmid isolated from said colonies; wherein the cells are from the U-2 OS human osteosarcoma cell line expressing a LexA-repressor fusion protein containing the LexA DNA binding domain and a coding region of HP1 or HPC2 under control of the Tet-Off transcriptional regulatory system, and wherein the cells comprise a plasmid comprising the DNA fragment having transcription modulating quality cloned into a polylinker sequence in said plasmid, positioned between four LexA operator sites and the SV40 promoter that controls the zeocin resistance gene, and wherein said zeocin resistance gene would otherwise be repressed due to the expression of the LexA-repressor fission protein but for the presence of said DNA fragment having transcription modulating quality.