L-myc cooperates with ras to transform primary rat embryo fibroblasts.
Recent molecular analysis has revealed that L-myc has several domains of extremely conserved amino acid sequence homology with c-myc and N-myc, suggesting similarity of function. We tested the biologic activity of L-myc by using an expression vector containing a cDNA clone coding for the major open reading frame in the 3.9-kilobase mRNA of L-myc under the control of a strong promoter (Moloney long terminal repeat) and found that L-myc complemented an activated ras gene in transforming primary rat embryo fibroblasts. However, the efficiency of transformation was 1 to 10% of that seen with the c-myc and simian virus 40 (SV40) controls. The L-myc/ras transformants initially grew more slowly than c-myc or SV40 transformants, but once established as continuous cell lines, they were indistinguishable from cell lines derived from c-myc/ras or SV40/ras transfectants as determined by morphology, soft-agar cloning, and tumorigenicity in nude mice.
Birrer
M J
MJ
NCI-Navy Medical Oncology Branch, National Cancer Institute, Naval Hospital, Bethesda, Maryland 20814.
Segal
S
S
DeGreve
J S
JS
Kaye
F
F
Sausville
E A
EA
Minna
J D
JD
D000818:Animals; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000032:analysis*; D004247:DNA / Q000032:analysis; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics*; D009368:Neoplasm Transplantation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D016283:Proto-Oncogene Proteins p21(ras); D012313:RNA / Q000032:analysis; D051381:Rats
D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012313:RNA; D004247:DNA; D016283:Proto-Oncogene Proteins p21(ras)