[Specific activity of the promoter containing Myc-Max response elements in c-myc-overexpressing cells].
OBJECTIVE
To investigate the specific activity of a hybrid promoter which is constructed by replacing the third domain of herpes simplex virus (HSV) thymidine kinase (TK) promoter with the Myc-Max response elements.


METHODS
Myc-Max response elements were ligated with a third domain-deleted HSV-TK promoter by cloning and subcloning PCR products. Then a luciferase-expressing plasmid, in which the luciferase gene was put under the control of hybrid promoter, was constructed and transfected transiently into the cell lines which had been demonstrated to be c-myc over- or low-expressing by Northern blot hybridization. The luciferase activities in these cells were detected.


RESULTS
In c-myc over-expressing cells, the hybrid promoter (Mpr) led to high levels of (81,966 +/- 43,238) relative light units (RLUs) in PC-2 cells and (70,563 +/- 22,435) RLUs in PC-7 cells, which were 78- and 150-fold higher than those coming from the third domain-deleted TK promoter (Epr), and also 6.9- and 1.7-fold higher than the activities controlled by TK promoter. However, Mpr showed a very low activity in c-myc low-expressing cells, in which the luciferase activity was (431 +/- 73) RLUs, similar to (601 +/- 141) RLUs produced by Epr.


CONCLUSIONS
The activity of hybrid promoter, which is composed of Myc-Max response elements and the third domain-deleted TK promoter, possesses cell-type specificity for c-myc-overexpressing cells.
Zhang
L
L
Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, PUMC, Beijing 100730.
Liu
T
T
Cui
Q
Q
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018139:Simplexvirus / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C499330:MAX protein, human; C067850:Myc associated factor X; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D014157:Transcription Factors; D013937:Thymidine Kinase