| 摘要 |
The present invention provides a novel cis-acting regulatory element that is required for maximal induction of the human low density lipoprotein (LDL) receptor gene following depletion of cellular sterols in HepG2 cells. In vivo dimethyl sulfate footprinting of the human LDL receptor promoter before and after transcriptional induction in HepG2 cells revealed protection of the sequence 5'-GAGCTTCACGGGTTAAAAAG-3' (SEQ ID NO.1), corresponding to nucleotides -126 to -145, (referred to as FP1). Further, presence of the FP1 sequence resulted in significant enhancement of luciferase reporter gene expression (approximately 375%) in response to low levels of sterols in HepG2 cells using promoter luciferase constructs. In addition, the enhancement was markedly attenuated on nucleotide substitutions within the FP1 site. Thus, the present invention discloses a novel regulatory element, FP1, in the human LDL receptor promoter and a vector containing this element. It is contemplated that FP1 can be used to confer sterol regulatory capability to heterologous genes ordinarily not under sterol regulation and be used in an assay to screen for compounds capable of stimulating cells to synthesize LDL receptors.
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