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Adenovirus E1B 19 kDa protein protects against cell death induced by viral infection and certain external stimuli. The Bcl-2 protein can functionally substitute for the E1B 19 kDa protein. To identify cellular targets for the 19 kDa protein, we used the two-hybrid screen in yeast. We have isolated cDNAs for three different proteins, designated Nip1, Nip2,(More)
The tat gene of HIV is a strong activator of the viral LTR. The Tat protein contains a highly basic domain that is important for its transport to the nuclear/nucleolar locations. The Tat basic domain when fused to Escherichia coli beta-galactosidase directed the chimeric protein to the nucleus and nucleolus. Tat mutants lacking the entire basic domain were(More)
The rev protein (Rev) of human immunodeficiency virus increases the cytoplasmic expression of viral structural gene mRNAs. We had previously reported the existence of a region (residues 73-98) near the carboxy-terminus in HIV-1 Rev essential for its function. To further define the structural elements in this region, we examined the effects of substitution(More)
We have investigated the role of mitochondrial Ca(2+) (Ca(m)) homeostasis in cell survival. Disruption of Ca(m) homeostasis via depletion of the mitochondrial Ca(2+) store was the earliest event that occurred during staurosporine-induced apoptosis in neuroblastoma cells (SH-SY5Y). The decrease of Ca(m) preceded activation of the caspase cascade and DNA(More)
The Bcl-2 homology 3 (BH3) domain is present in most members of the Bcl-2 protein family and is required to confer the death-inducing properties of pro-apoptotic members, including Bax, Bak, Bad, and Bik, in cell-based assay systems. To determine whether the BH3 domain possesses a similar role in tumor tissues in vivo, we overexpressed the wild-type Bik(More)
The bel1 gene of human spumaretrovirus (HSRV) encodes a 300-amino-acid nuclear protein termed Bel1 that is a potent activator of transcription from the cognate long terminal repeat (LTR). Bel1 can also efficiently activate the human immunodeficiency virus type 1 (HIV-1) LTR. We have previously shown that the amino-terminal 227-residue region (minimal(More)
The bel1 gene of human spumaretrovirus (HSRV) codes for a 300-amino-acid nuclear protein, termed Bel1, that can strongly activate transcription from the cognate long terminal repeat (LTR) by at least 200-fold. Bel1 can also activate human immunodeficiency virus type 1 (HIV-1) LTR expression. By using site-directed mutagenesis, we have identified distinct(More)
The human spumaretrovirus (HSRV) genome contains, in addition to coding information for the structural proteins, open reading frames (ORFs) for at least three additional genes termed bel1, bel2 and bel3. We report here the localization of the transcriptional activator of HSRV to the bel1 ORF. In reporter-based transient expression assays in COS cells(More)
The rev gene of human immunodeficiency virus type 1 (HIV-1) encodes a 116 amino acid nuclear regulatory protein (Rev) that increases the cytoplasmic expression of viral mRNAs containing the Rev response element (RRE) and coding for the structural proteins, Gag and Env. To identify the functional domains of Rev, amino acid deletion and chain termination(More)
The Rev protein of human immunodeficiency virus type 1 (HIV-1) is essential for the nucleocytoplasmic transport of unspliced and partially spliced HIV mRNAs containing the Rev response element (RRE). In a yeast two-hybrid screen of a HeLa cell-derived cDNA expression library for human factors interacting with the Rev leucine-rich nuclear export sequence(More)