Laboratory of Molecular Biology

About: Laboratory of Molecular Biology is a facility organization based out in Cambridge, Cambridgeshire, United Kingdom. It is known for research contribution in the topics: Gene & RNA. The organization has 19395 authors who have published 24236 publications receiving 2101480 citations.

A retrovirus carrying an MDR1 cDNA confers multidrug resistance and polarized expression of P-glycoprotein in MDCK cells.

Abstract: A full-length cDNA for the human multidrug resistance gene 1 (MDR1) has been inserted into a retroviral vector containing a murine Harvey sarcoma virus from which the viral oncogene was deleted. Ecotropic and amphotropic virus was produced after transfection of this vector into psi-2 and PA-12 packaging cell lines. This virus conferred the full phenotype of multidrug resistance on mouse and human cell lines. Viral titers of up to 2 X 10(5) drug-resistant colonies per ml were observed. Infected cells became resistant to colchicine, vinblastine, doxorubicin, VP16 (etoposide), and puromycin, but not cisplatin, indicating that the presence of the human MDR1 gene is sufficient to cause multidrug resistance. When the dog kidney cell line MDCK was infected with the MDR1 virus, P-glycoprotein was expressed in a polarized manner on the upper surface of the cells, showing that the cloned cDNA also encodes information for polarized expression of P-glycoprotein. The MDR1 virus should be useful for introducing this drug resistance gene into a variety of cell types for biological experiments in vitro and in vivo.

Human dopamine D1 receptor encoded by an intronless gene on chromosome 5.

Abstract: RECEPTORS for dopamine have been classified into two functional types, D1 and D2 (refs 1,2). They belong to the family of receptors acting through G (or guanine nucleotide-binding) proteins3. D2 receptors inhibit adenylyl cyclase, but D1 receptors stimulate adenylyl cyclase and activate cyclic AMP-dependent protein kinases4,5. Dopamine D1 and D2 receptors are targets of drug therapy in many psychomotor disorders, including Parkinson's disease and schizophrenia6,7, and may also have a role in drug addiction and alchoholism8. D1 receptors regulate neuron growth and differentiation9, influence behaviour and modify dopamine D2 receptor-mediated events10,11. We report here the cloning of the D1 receptor gene, which resides on an intronless region on the long arm of chromosome 5, near two other members of the G-linked receptor family. The expressed protein, encoded by 446 amino acids, binds drugs with affinities identical to the native human D1 receptor. The presence of a D1 receptor gene restriction fragment length polymorphism will be helpful for future disease linkage studies.

HIV-1 protease inhibitors are substrates for the MDR1 multidrug transporter.

Abstract: The FDA approved HIV-1 protease inhibitors, ritonavir, saquinavir, and indinavir, are very effective in inhibiting HIV-1 replication, but their long-term efficacy is unknown. Since in vivo efficacy depends on access of these drugs to intracellular sites where HIV-1 replicates, we determined whether these protease inhibitors are recognized by the MDR1 multidrug transporter (P-glycoprotein, or P-gp), thereby reducing their intracellular accumulation. In vitro studies in isolated membrane preparations from insect cells infected with MDR1-expressing recombinant baculovirus showed that these inhibitors significantly stimulated P-gp-specific ATPase activity and that this stimulation was inhibited by SDZ PSC 833, a potent inhibitor of P-gp. Furthermore, photoaffinity labeling of P-gp with the substrate analogue [125I]iodoarylazidoprazosin (IAAP) was inhibited by all three inhibitors. Cell-based approaches to evaluate the ability of these protease inhibitors to compete for transport of known P-gp substrates showe...