Krummrei U, Bang R, Schmidtchen R, Brune K, Bang H
Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nürnberg, Germany.
FEBS Lett. 1995 Aug 28;371(1):47-51. doi: 10.1016/0014-5793(95)00815-q.
The association of cyclosporin A (CsA) immunosuppression with inhibition of transcription factor-dependent lymphokine gene activation formed the basis of our decision to investigate nuclear-associated Cyp isoforms. Immunofluorescence microscopy of mouse macrophages cell line with a monoclonal antibody mAb7F1 raised against CypA shows a co-localisation of CypA in the nucleus and in the cytosol. Nuclear CypA binds to DNA in a zinc ion-dependent manner, in contrast to recombinant CypB. Peptidyl-prolyl cisltrans isomerase (PPIase) activity of nuclear CypA is inhibited by zinc ions. The zinc inhibited CypA does not bind cyclosporin A (CsA). We suggest that nuclear Cyp in complex with zinc ions recognizes DNA sequences and is involved in transcription modulating processes.
