Lactoferrin (LF) promoter transfection and nucleotide sequence.

(A) Transient transfection of LF promoter plasmids in 32Dwt18 (myeloid) and MEL (nonmyeloid) cells. LF promoter fragments (LF89, LF167, LF237, and LF 649) were cloned into the promoterless pGL3B vector and transiently transfected into 32Dwt18 and MEL cells, along with pCMVβgal plasmid. Cells were harvested 24 hours after transfection and luciferase reporter gene activity was measured. The figure represents the mean ± SE value from 3 independent experiments, each performed in duplicate. Normalized luciferase values are represented as a ratio of luciferase activity to pGL3B luciferase activity. (B) Nucleotide sequence of the human LF promoter and its 5′ flanking sequence. The position of the LF89 (−89 base pairs [bps]) is indicated. Putative binding sites for Sp1, Ets, C/EBP, and Myb transcription factors are indicated.