L factor, originally discovered in a subclone of mouse L cells, is a multicopy mammalian plasmid whose structure is related to that of polyoma. When a composite DNA consisting of L factor, pBR, bacterial neo, and an immunoglobulin (kappa) gene was introduced into mouse myeloma cells, the DNA was established as plasmids in the cells without rearrangement or integration into the chromosomes. The plasmid-bearing myeloma cells produced kappa mRNA and the gene product, kappa immunoglobulin, which were apparently derived from the gene located on plasmid L factor. These results suggest that L factor can be used as a plasmid expression vector for studies on gene expression and production of biologically active substances in mammalian cells.
ASJC Scopus subject areas
- Molecular Biology