Gene transcription and ionizing radiation: methods and compositions

Abstract

The present invention provides a DNA molecule comprising a radiation responsive enhancer-promoter operatively linked to an encoding region that encodes at least one polypeptide. An encoding region can comprise a single encoding sequence for a polypeptide or two or more encoding sequences encoding DNA binding, activation or repression domains of a transcription factor. Processes for regulating polypeptide expression and inhibiting tumor growth using such DNA molecules are also provided.

1 . A synthetic DNA molecule comprising a radiation responsive enhancer-promoter operatively linked to an encoding region that encodes at least one polypeptide, which encoding region is operatively linked to a transcription-terminating region.  
   
   
       2 . The DNA molecule according to  claim 1  wherein said radiation responsive enhancer-promoter comprises a CArG domain of an Egr-1 promoter, a tumor necrosis factor-α promoter or a c-Jun promoter.  
   
   
       3 . The DNA molecule according to  claim 1  wherein said encoding region encodes a polypeptide having the ability to interfere with the structural or functional integrity of a cell.  
   
   
       4 . The DNA molecule according to  claim 3  wherein said polypeptide is a cytokine, a dominant negative, a tumor suppressing factor, an angiogenesis inhibitor or a monocyte chemoattractant.  
   
   
       5 . The DNA molecule according to  claim 3  wherein said polypeptide is tumor necrosis factor-α, interleukin-4, JE, ricin, PF4  Pseudomonas  toxin, p53, the retinoblastoma gene product or the Wilms' tumor gene product.  
   
   
       6 . The DNA molecule according to  claim 3  wherein said polypeptide protects a normal cell from the pathological effects of radiation.  
   
   
       7 . The DNA molecule according to  claim 6  wherein said polypeptide is interleukin-1, interleukin-6, tumor necrosis factor-α, a tissue growth factor, a tissue growth factor receptor or a free radical scavenger.  
   
   
       8 . The DNA molecule according to  claim 7  wherein said tissue growth factor is a hematopoietic growth factor, a hepatocyte growth factor, a kidney growth factor, an endothelial growth factor or a vascular smooth muscle growth factor.  
   
   
       9 . The DNA molecule according to  claim 6  wherein said polypeptide is a colony stimulating factor such as GM-CSF, G-CSF or M-CSF; interleukin-3; basic fibroblast growth factor; platelet derived growth factor; or manganese superoxide dismutase.  
   
   
       10 . The DNA molecule according to  claim 3  wherein said polypeptide has anticoagulant, thrombotic or thrombolytic activity.  
   
   
       11 . The DNA molecule according to  claim 10  wherein said polypeptide is plasminogen activator, a plasminogen activator inhibitor or a streptokinase.  
   
   
       12 . The DNA molecule according to  claim 3  wherein said polypeptide catalyses the conversion of a pro-drug to a drug.  
   
   
       13 . The DNA molecule according to  claim 12  wherein said polypeptide is herpes simplex virus thymidine kinase or a cytosine deaminase.  
   
   
       14 . The DNA molecule according to  claim 3  wherein said polypeptide is a surface antigen product of a major histocompatibility complex gene.  
   
   
       15 . The DNA molecule according to  claim 14  wherein said antigen product is HLA-A, HLA-B or HLA-C.  
   
   
       16 . The DNA molecule according to  claim 1  wherein said transcription-terminating region comprises nucleotides 1533 to about 2157 of the human growth hormone gene.  
   
   
       17 . The DNA molecule according to  claim 1  wherein said encoding region encodes a whole or a portion of more than one polypeptide.  
   
   
       18 . The DNA molecule according to  claim 17  wherein said encoding region comprises: 
 (a) a first encoding sequence that encodes a DNA binding domain of a first transcription factor;    (b) a second encoding sequence that encodes an activation or repression domain of a second transcription factor;    (c) a third encoding sequence that encodes a nuclear localization signal, whereby the first, second and third encoding sequences are operatively linked in frame to each other in any order with the proviso that said third encoding sequence need be present only if said first or second encoding sequence does not encode a nuclear localization signal; and    (d) a transcription-terminating region that is operatively linked to any of the first, second or third encoding sequences such that the transcription-terminating region is located 3′ to all of the first, second and third encoding sequences.    
   
   
       19 . The DNA molecule according to  claim 18  wherein said first transcription factor is GAL4.  
   
   
       20 . The DNA molecule according to  claim 18  wherein said second encoding sequence encodes the VP-16 or NF-κB activation domain.