Trans-activation of the long terminal repeat of human immunodeficiency virus type 1 by the parvovirus B19 NS1 gene product

1 Service de Bactériologie et Virologie, Hôpital Saint-Louis, 1 avenue Claude Vellefaux, 75010 Paris and 2 INSERM U332, Institut Cochin de Génétique Moléculaire, 22 rue Méchain, 75014 Paris, France Persistent parvovirus B19 infections in human immuno-deficiency virus type 1 (HIV-1)-infected patients have been reported. The two viruses could share common target cells. The NS1 protein of B19 regulates B19 expression and we have investigated its possible effect on the long terminal repeat (LTR) of HIV-1. In transient transfection experiments, NS1 trans-activated the expression of reporter genes under the control of the HIV-1 LTR. The effect of NS1 was apparent only in the presence of the HIV-1 Tat protein, and required intact TAR and TATA box sequences. Received 26 January 1993; accepted 5 May 1993.