Transferrin (Tf) is a liver-derived iron transport protein whose plasma concentration
increases following exposure to hypoxia. Here, we present a cell culture model capable of
expressing Tf mRNA in an oxygen-dependent manner. A 4-kilobase pair Tf
promoter/enhancer fragment as well as the 300-base pair liver-specific Tf enhancer alone
conveyed hypoxia responsiveness to a heterologous reporter gene construct in hepatoma
but not HeLa cells. Within this enhancer, a 32-base pair hypoxia-responsive element was …