Expression of oncomodulin does not lead to the transformation or immortalization of mammalian cells in vitro.
A recombinant plasmid (pMTONCO) containing the coding sequences for rat oncomodulin under the direction of the metallothionein promoter was constructed. pMTONCO was co-transfected with the pSV2-NEO plasmid into primary mouse kidney cells or Rat-1 cells using the calcium phosphate technique and stable transformants were isolated after selection with G418. Transcription from the metallothionein promoter was inducible with heavy metals and produced an oncomodulin-specific mRNA. The presence of oncomodulin protein in stable cell lines was verified by immunoprecipitation with specific antisera. While a plasmid encoding the polyomavirus T-antigens was able to prolong the life-span of primary mouse kidney cells in culture, no equivalent activity was noted when the pMTONCO plasmid was used to transfect primary cells. When expressed in Rat-1 cells, oncomodulin did not affect the growth properties of these cells, nor did it predispose cells to higher frequencies of oncogenic transformation to a viral oncogene. We conclude that oncomodulin is neither an immortalizing nor transforming agent in vitro.
Mes-Masson
A M
AM
Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec.
Masson
S
S
Banville
D
D
Chalifour
L
L
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology; D010957:Plasmids; D051381:Rats; D014170:Transformation, Genetic
D002135:Calcium-Binding Proteins; D009363:Neoplasm Proteins; C034733:oncomodulin