Low-level beta 1 protein kinase C expression in cloned rat embryo fibroblast cells enhances transformation induced by the adenovirus type 5 E1A gene.
Expression of the E1A gene of adenovirus type 5 (Ad5) in a cloned rat embryo fibroblast (CREF) cell line results in morphological transformation. The efficiency of E1A-mediated transformation of CREF cells is increased if a wild-type Ad5 E1A gene is cotransfected with a rat beta 1 protein kinase C (beta 1 PKC) gene. A direct demonstration of complementation between a functional-transforming Ad5 E1A gene and beta 1 PK in inducing transformation was demonstrated using Ad5 E1A cold-sensitive mutant (E1Acs) genes. The E1Acs gene enhanced transformation only at the transformation-permissive temperature of 37 degrees C and not at the nonpermissive transforming temperature of 32 degrees C. CREF cells constitutively expressing low levels of beta 1 PKC mRNA were transformed at a higher frequency than parental CREF cells after transfection with an Ad5 E1A gene or infection with wild-type Ad5 or the Ad5 host-range cold-sensitive mutant H5hr1. There was no enhancement of transformation in low-level beta 1 PKC-expressing CREF cells when cultures were grown continuously in the presence of the PKC-inhibitor 1-(5-isoquinolynsulfonyl)-2-methylpiperazine dihydrochloride. Transfected CREF cells expressing low levels of beta 1 PKC mRNA displayed CREF-like morphology and did not form colonies when grown in agar. In contrast, retroviral vector-transformed CREF cells expressing high levels of beta 1 PKC mRNA and beta 1 PKC enzyme activity were morphologically transformed and grew efficiently in agar. These findings indicate that the beta 1 PKC gene, when expressed at low levels, can cooperate with the Ad5 E1A gene in the initiation of viral oncogene-mediated transformation.
Su
Z Z
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Department of Neurosurgery, Columbia University, College of Physicians and Surgeons, New York, New York 10032.
Duigou
G J
GJ
Fisher
P B
PB
D017456:Adenovirus Early Proteins; D000260:Adenoviruses, Human / Q000235:genetics*; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002999:Clone Cells; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D015870:Gene Expression; D005814:Genes, Viral; D046911:Macromolecular Substances; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D011493:Protein Kinase C / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D013696:Temperature; D014162:Transfection
D017456:Adenovirus Early Proteins; D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D046911:Macromolecular Substances; D009856:Oncogene Proteins, Viral; D012333:RNA, Messenger; D004247:DNA; D011493:Protein Kinase C