ABSTRACT
Sterol carrier protein2 (SCP2) is a 13.2-kD protein that is thought to be involved in the intracellular transport of cholesterol. Using synthetic oligonucleotides based on the protein sequence of SCP2, a clone (SP43) was isolated from a rat liver cDNA library. The DNA sequence revealed that the cDNA could encode a polypeptide of 273 amino acids (28.9 kD) or 143 amino acids (15.3 kD) in which the carboxy-terminal 123 amino acids are identical to the SCP2 protein. RNA blot hybridization revealed that a variety of rat tissues contain a homologous RNA of a size similar to SP43 (approximately 1.5 kb). Levels of SCP2 mRNA increased in parallel with cytochrome P450scc mRNA in the immature gonadotropin-primed rat ovary. The isolation of a cDNA clone encoding SCP2 will facilitate studies on its role in cholesterol metabolism.
Subject(s)
Carrier Proteins/genetics , DNA/isolation & purification , Plant Proteins , Sterols/metabolism , Amino Acid Sequence , Animals , Base Sequence , Blotting, Southern , Chorionic Gonadotropin/pharmacology , Cloning, Molecular , DNA Probes , Female , Gonadotropins, Equine/pharmacology , Liver/analysis , Molecular Sequence Data , Ovary/metabolism , Protein Biosynthesis , RNA, Messenger/metabolism , Rats , Transcription, Genetic/drug effectsABSTRACT
Since HIV tat function is essential for the HIV infectious cycle, it represents an important possible target of therapeutic intervention for HIV infection. Stable human cell lines were derived that express high levels of beta-galactosidase under the combined control of the transacting HIV-1 tat gene product and the cis-acting HIV-1 LTR. The tat gene product induces LTR-linked gene expression approximately 1000-fold in this system. The high level of expression of beta-galactosidase under HIV tat and LTR control in stable cell lines allows rapid spectrophotometric quantitation of beta-galactosidase enzymatic activity from fewer than 5000 cells seeded in a microtiter plate well. Such cell lines provide a virus-free system for the high-capacity screening of compounds for the ability to interfere with HIV tat-mediated transactivation of gene expression.
