SIMILAR ORGANIZATION OF THE LIPOPOLYSACCHARIDE-BINDING PROTEIN (LBP) AND PHOSPHOLIPID TRANSFER PROTEIN (PLTP) GENES SUGGESTS A COMMON GENE FAMILY OF LIPID-BINDING PROTEINS

The transfer of lipids in aqueous environments such as serum has been attributed to a recently characterized class of proteins. Abnormal reg ulation of serum lipids by these proteins is thought to be a key event in the pathophysiology of cardiovascular diseases. Lipopolysaccharide (endotoxin) binding protein (LBP) was identified by virtue of its abi lity to bind bacterial lipid A. We have analyzed the exon-intron organ ization of the LBP gene and the nucleotide sequence of its approximate ly 20 kb spanning 5'- and 3'-untranslated regions. When comparing the genomic organization of LBP with that of two other genes coding for li pid transfer proteins, significant homologies were found. The LBP gene includes 15 exons, and the 2-kb promoter contains recognition element s of acute phase-typical reactants and a repetitive 12-mer motif with an as yet unknown protein-binding property. Detailed sequence comparis on revealed a closer relatedness of LBP with PLTP than with CETP as de monstrated by an almost identical intron positioning. This high degree of similarity supports functional studies by others suggesting that l ike LBP, PLTP may also be able to bind and transport bacterial lipopol ysaccharide. (C) 1997 Academic Press.