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

Persistent parvovirus B19 infections in human immunodeficiency 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.