GENE REGULATION IN TERATOCARCINOMA AND EMBRYONIC CELLS

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Plasminogen activators are serine proteases that have been implicated in a wide variety of normal and abnormal processes. The experiments proposed address two broad questions concerning these enzymes: how is the synthesis of tissue plasminogen activator (tPA) controlled, and what are the respective roles for tPA and the urokinase-type plasminogen activator (uPA). Regulation of tPA synthesis will be studied in F9 teratocarcinoma cells, in which enzyme production can be conveniently controlled by manipulation of the culture conditions. The fact that tPA can feedback inhibit its own synthesis will also be examined in these cells by classical techniques and oligonucleotide-mediated mutagenesis followed by transfection and expression of specifically modified enzymes. The tumorigenic properties of F9 cells producing these modified tPAs will also be determined. In the rat ovary, granulosa cells produce tPA and thecal cells produce uPA. With both cells, enzyme synthesis is maximal at the time of ovulation and is induced by gonadotropins. This system will be used in vivo and in vitro to investigate the function of the two enzymes in the ovulatory process. The possibility that tPA is instrumental in degrading follicular proteoglycans, and that proteoglycans can stimulate the activity of tPA, will be examined.