A point mutation in the first splice donor leads to reduced oncogenic properties of the adenovirus serotype 12 E1A gene.
Cells transformed by proteins of early regions 1A (E1A) and 1B (E1B) of oncogenic adenovirus serotype 12 (Ad12) grow to tumours in syngeneic, immunocompetent rodents. To gain insight into the mechanisms of oncogenic transformation, we point mutated the first splice donor in the Ad12-E1A gene, leading to the loss of the Ad12-E1A(9.5S) and Ad12-E1A(11S/10S) proteins and to a conservative amino acid (aa) exchange at position aa 30 (valine vs. leucine) in the Ad12-E1A(13S) and Ad12-E1A(12S ) proteins. BMK cells transformed by mutant Ad12-E1A (Ad12-E1Am) plus Ad12-E1B via retrovirus-mediated gene transfer showed features comparable to wild-type Ad12-E1A (Ad12-E1Awt) plus Ad12-E1B-transformed cells: they formed foci in soft agar and produced tumours in immunodeficient nude mice, although after a prolonged latency period. These results suggest that Ad12-E1A(9.5S) and Ad12-E1A(11S/10S) are dispensable for cellular transformation. However, in contrast to Ad12-E1Awt cells, Ad12-E1Am cells failed to grow to tumours in syngeneic, immunocompetent rodents, with the exception of one cell line, which produced tumours in about 50% of the immunocompetent animals. Interestingly, the concentration of the putative tumour suppressor and co-activator p300 was elevated in cell lines expressing high levels of Ad12-E1A and Ad12-E1B due to an increased half-life. These results indicate that p300 is stabilized in Ad12-E1-transformed BMK cells, probably by a mechanism linked to high expression of Ad12-E1A/E1B.
Lehmkühler
Oliver
O
Institute of Molecular Biology (Cancer Research), University of Essen Medical School, Essen, Germany.
Kühn
Claudine
C
Gunawardena
Bettina
B
Esche
Helmut
H
Brockmann
Dieter
D
D000256:Adenoviridae / Q000145:classification / Q000472:pathogenicity; D017500:Adenovirus E1A Proteins / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D050881:E1A-Associated p300 Protein; D006367:HeLa Cells; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000209:etiology; D009687:Nuclear Proteins / Q000032:analysis / Q000502:physiology; D017354:Point Mutation; D012703:Serotyping; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000032:analysis / Q000502:physiology
D017500:Adenovirus E1A Proteins; D015395:Histocompatibility Antigens Class I; D009687:Nuclear Proteins; D015534:Trans-Activators; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse