RECOMBINANT MOUSE-CELL LINES TRANSFORMED WITH DIFFERENT TYPE-1 BOVINEPAPILLOMA VIRUS-BASED VECTORS AND EXPRESSING HUMAN TISSUE-PLASMINOGENACTIVATOR .1. ANALYSIS OF CELL-LINES PRODUCING RECOMBINANT TISSUE-PLASMINOGEN ACTIVATOR

Recombinant C127 cell lines obtained previously [1] by transformation with vectors based on full-length BPV1 DNA or its mutant Lx1 with dupl icated LCR-E6-E7 region were characterized. All vectors contained huma n tissue plasminogen activator (tPA) cDNA under the control of the mou se MT1 promoter. Lx1-based vectors have a higher copy number than thei r BPV1-based analogs; vector DNA is mainly integrated into the genome. The procedure for induction of tPA synthesis in C1.23 cells was optim ized to attain an eightfold increase in tPA in the culture medium. Nat ive and deglycosylated variants of recombinant tPA synthesized in C1.2 3 cells and human tPA produced by Bowes melanoma are virtually identic al in their properties.