Promoter of the gene encoding the 16 kDa DNA-binding and apoptosis-inducing C1D protein

The 5' region of the gene encoding the human 16 kDa DNA-binding and apoptos is-inducing C1D protein was analysed for promoter activity. Sections of thi s region were cloned into a promoterless vector containing the enhanced gre en fluorescent protein (EGFP) as reporter gene. Expressed EGFP was estimate d in transfected cells by quantitative fluorescence microscopy. The sequenc e between mRNA positions ATG -868 and ATG -12 results in relatively highest EGFP expression in transiently transfected human and murine cells. The ups tream segment immediately adjacent to the 5' end of the most active fragmen t was identified as an inverted LINE-1 repeat element. Transient transfecti on experiments point to the presence of cis-acting repressing sequences on this LINE-1 element which reduce the transcriptional activity of the basal C1D promoter in human and murine cells by more than 95%. This result suppor ts previous evidence suggesting that LINE-1 sequences may function as regul atory elements to control the expression of nearby genes. (C) 2001 Elsevier Science B.V. All rights reserved.