Den Kulturella Hjärnan

The homepage www.kulturellahjarnan.se contains scientific publications. recorded lectures and interviews within the field Culture,Brain and HealthHemsidan www.kulturellahjarnan.se redovisar vetenskapliga publikationer, inspelade föredrag och intervjuer inom området Kultur,Hjärna och Häls

Transcriptional regulation of the human carboxyl ester lipase gene in THP-1 monocytes: an E-box required for activation binds upstream stimulatory factors 1 and 2.

The bile salt-stimulated carboxyl ester lipase (CEL) is important for the digestion and absorption of dietary lipids, and is expressed at high levels by the exocrine pancreas and the lactating mammary gland. However, the presence of CEL in human plasma suggests that the role of CEL in lipid metabolism may stretch beyond its function in the intestinal lumen, and possibly include interactions with cholesterol and oxidized lipoproteins to modulate the progression of atherosclerosis. We have used the CEL-expressing human monocytic cell line THP-1 to investigate the transcriptional regulation of the human CEL in monocytes. Analyses of the promoter region revealed that an E-box located at -47/-52 is necessary for CEL expression. Point mutations in the E-box almost completely abolish the transcriptional activity. Electrophoretic mobility-shift assay analyses reveal that the E-box binds the upstream stimulatory factors 1 and 2, and the binding of an upstream stimulatory factor-containing complex in THP-1 cells also requires the presence of a putative nuclear receptor-binding site at -60/-66. Furthermore, we demonstrate that the E-box is also necessary for CEL expression in the pancreas and the mammary gland, although there are tissue-specific requirements for additional activating elements

cDNA CLONING AND SEQUENCING OF HUMAN MILKBILE SALTSTIMULATED LIPASE

Wehave isolated and sequenced cDNAclones covering the entire coding sequence of human milk bile salt-stimulated lipase (BSSL). The deduced amino acid sequence starts with a 21 residues leader peptide. The open reading frame continues with 722 amino acid residues. The sequence contains in the C-terminal part a proline-rich repeat, 16 repeats of 11 amino acid residues each. The mRNAwasestimated to be approximately 2500 nt from Northern blot. The cDNAis 2432 bases long, which indicates that a near full-length copy of the transcript have been isolated. Comparisons with other enzymes show that BSSL is a new memberofthe supergene family of serine hydrolases. Not only is it closely related (in the N-terminal half virtually identical) to lysophospholipase from rat pancreas and cholesterol esterase from bovine pancreas, but also shows a high degree of homology to several esterases, e.g. acetyl choline esterase. It contains the sequence which has been proposedto be the acetylcholine binding site in acetyl choline esterase. In contrast, no such homologies could be found to typical lipases, with the exception of the consensus sequence GXSXGtypical for serine hydrolases