Phosphatidylcholine transfer protein (PC-TP) Is a cytosolic lipid transfer
protein that promotes intermembrane transfer of phosphatidylcholines but no
other phospholipids. Although its physiological function remains unknown,
phosphatidylcholine transfer protein is enriched in liver and evidence from
model systems suggests a role in hepatocellular selection and transport of
biliary phospholipids. To facilitate in vivo studies, a cDNA encoding rat
PC-TP was cloned by library screening and 5'-rapid amplification of cDNA en
ds. Genomic cloning demonstrated the rat Pctp gene spans 10.8 kb and is com
prised of six exons. The putative transcription initiation site was identif
ied 50 bp upstream of the translation initiation site. Nucleotide sequence
analysis of the 5'-flanking region revealed a CAAT- but no TATA-box. Transi
ent transfection of a series of 5'-deleted Pctp-promoter-firefly luciferase
constructs into Reuber H35 rat hepatoma cells, which express Pctp mRNA, an
d Gunn rat fibroblasts, which do not, suggest that cis-acting elements in a
637 bp promoter region contribute to enhanced expression of PC-TP in liver
. (C) 1999 Elsevier Science B.V. All rights reserved.