{TAIL ~ The recombinant transfection system} 22, wherein the transcriptional regulatory sequence is {HEAD ~ a conditional transcriptional regulatory sequence} 
{ TAIL ~ The recombinant transfection system } 22 , wherein the transcriptional regulatory sequence is { HEAD ~ a conditional transcriptional regulatory sequence }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD