The fos gene product undergoes extensive post-translational modification in eukaryotic but not in prokaryotic cells.
To investigate the properties of the fos oncogene, we have constructed bacterial and yeast vectors which express the entire fos-coded protein (Fos) and two C-terminal deletion products. In Escherichia coli, Fos proteins were expressed from the phage lambda pL promotor under the control of the temperature-sensitive lambda repressor. In vitro transcription/translation studies indicate that these vectors produce Fos proteins of the expected sizes. However, in vivo, Fos protein accumulation is observed only in hosts with the Lon- phenotype. In Saccharomyces cerevisiae, the fos gene was expressed from the PHO5 promoter which is induced under low-phosphate conditions. In contrast to the situation in E. coli, in which the heterologous proteins appeared as single major products when subjected to sodium dodecyl sulfate - polyacrylamide gel electrophoresis, the Fos proteins in S. cerevisiae displayed extensive Mr heterogeneity. Pulse-chase analyses indicated that this heterogeneity was a consequence of extensive post-translational modification. These modifications occurred to an equivalent extent on the products coded by the fos gene with C-terminal deletions and thus appear not to be controlled by the missing domain.
D000818:Animals; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D005822:Genetic Vectors; D051379:Mice; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D009857:Oncogenes; D012516:Osteosarcoma / Q000382:microbiology; D010957:Plasmids; D011499:Protein Processing, Post-Translational; D012190:Retroviridae / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D009856:Oncogene Proteins, Viral; D004262:DNA Restriction Enzymes