UMLS:C0021051 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cDNAs for two DNA binding proteins of BTE, a GC box sequence in the promoter region of the P-450IA1(CYP1A1) gene, have been isolated from a rat liver cDNA library by using the BTE sequence as a binding probe. While one is for the rat equivalent to human Sp1, the other encodes a primary structure of 244 amino acids, a novel DNA binding protein designated BTEB. Both proteins contain a zinc finger domain of Cys-Cys/His-His motif that is repeated three times with sequence similarity of 72% to each other, otherwise they share little or no similarity. The function of BTEB was analysed by transfection of plasmids expressing BTEB and/or Sp1 with appropriate reporter plasmids into a monkey cell line CV-1 and compared with Sp1. BTEB and Sp1 activated the expression of genes with repeated GC box sequences in promoters such as the simian virus 40 early promoter and the human immunodeficiency virus-1 long terminal repeat promoter. In contrast, BTEB repressed the activity of a promoter containing BTE, a single GC box of the CYP1A1 gene that is stimulated by Sp1. When the BTE sequence was repeated five times, however, BTEB turned out to be an activator of the promoter. RNA blot analysis showed that mRNAs for BTEB and Sp1 were expressed in all tissues tested, but their concentrations varied independently in tissues. The former mRNA was rich in the brain, kidney, lung and testis, while the latter was relatively abundant in the thymus and spleen.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Two regulatory proteins that bind to the basic transcription element (BTE), a GC box sequence in the promoter region of the rat P-4501A1 gene. 135 62

Purified integrase protein (IN) can nick linear viral DNA at a specific site near the ends and integrate nicked viral DNA into target DNA. We have made a series of 43 site-directed point mutants of human immunodeficiency virus type 2 IN and assayed purified mutant proteins for the following activities: site-specific cleavage of viral DNA (donor cut), integration (strand transfer), and disintegration. In general, the different activities were similarly affected by the mutations. We found three mutations that (almost) totally abolished IN function: Asp-64-->Val, Asp-116-->Ile, and Glu-152-->Leu, whereas 25 mutations did not affect IN function. A few mutations affected the different activities differentially. Near the amino terminus a zinc finger-like sequence motif His-Xaa3-His-Xaa20-30-Cys-Xaa2-Cys is present in all retroviral IN proteins. Two mutations in this region (His-12-->Leu and Cys-40-->Ser) strongly inhibited donor cut but had less effect on strand transfer. The central region of IN is most highly conserved between retroviral INs. Three mutants in this region (Asn-117-->Ile, Asn-120-->Leu, and Lys-159-->Val) were inhibited in strand transfer but were inhibited less strongly in donor cut. Mutation of Asn-120 (to glycine, leucine, or glutamate) resulted in changes in integration-site preference, suggesting that Asn-120 is involved in interactions with target DNA. We did not find a mutant in which one activity was lost and the others were unaffected, supporting the notion that IN has only one active site for the catalysis of donor cut and strand transfer.
...
PMID:Mutational analysis of the integrase protein of human immunodeficiency virus type 2. 140 71

The nucleocapsid protein (NC) of all animal retroviruses, encoded by the gag gene, is the major structural protein of the core ribonucleoprotein complex, bound to genomic RNA in mature virions. NC is also thought to play one or more accessory roles in reverse transcription. Mature NC (p7NC) from human immunodeficiency virus type 1 (HIV-1) is a 71-amino acid, basic protein which contains two Cys3His Zn(II) retroviral-type zinc finger domains. Herein, we describe the subcloning and expression of HIV-1 NC, denoted NC71, from an inducible phage T7 RNA polymerase promoter in Escherichia coli. Purified NC71 can be reversibly reconstituted with 2 g.at Zn(II) determined by atomic absorption. Ultraviolet circulation dichroism spectroscopy has been used to characterize the complexes between highly purified NC71 and the RNA homopolynucleotide poly(A) and E. coli tRNA(mixed). On poly(A), Zn2 NC71 is characterized by an apparent site size n = 15 +/- 3 nucleotides and high affinity (Kapp = 3 x 10(7) M-1) and moderately cooperative (omega approximately 170 +/- 25) binding. A mixture of E. coli tRNA species (tRNA(mixed) was used to probe the conformational changes induced in tRNA upon binding of HIV-1 NC71. Two structural forms of tRNA(mixed), which differ in their degree of tertiary structure, were assayed for their susceptibility to denaturation by NC71. Five molar monomer equivalents of NC71 are required to denature the "inactive" tRNA in the absence of Mg2+. A Zn(II)-free, oxidized form of NC71 was also shown to unwind inactive tRNA with the same efficiency and stoichiometry. The detailed spectral changes which occur on NC-induced denaturation closely mimic temperature-induced denaturation of inactive tRNA(mixed). The prototype helix-destabilizing protein, T4 gene 32 protein, is unable to unwind this form of tRNA under the same conditions. The stoichiometry of unwinding of inactive tRNA by NC71 is consistent with the site size determined with poly(A). An "active" form of tRNA(mixed), prepared by thermal denaturation and refolding of the inactive form with Mg2+, proved less susceptible to both temperature and NC71-induced unwinding. The mechanistic implications of these findings on the reported biochemical activities of RNA:RNA annealing and replication primer tRNA positioning by NC are discussed.
...
PMID:Recombinant human immunodeficiency virus type 1 nucleocapsid (NCp7) protein unwinds tRNA. 155 77

The N-terminal domain of human immunodeficiency virus (HIV-1) integrase (IN) contains the sequence motif His-Xaa3-His-Xaa23-Cys-Xaa2-Cys, which is strongly conserved in all retroviral and retrotransposon IN proteins. This structural motif constitutes a putative zinc finger in which a metal ion may be coordinately bound by the His and Cys residues. A recombinant peptide, IN(1-55), composed of the N-terminal 55 amino acids of HIV-1 IN was expressed in Escherichia coli and purified. Utilizing a combination of techniques including UV-visible absorption, circular dichroism, Fourier transform infrared, and fluorescence spectroscopies, we have demonstrated that metal ions (Zn2+, Co2+, and Cd2+) are bound with equimolar stoichiometry by IN(1-55). The liganded peptide assumes a highly ordered structure with increased alpha-helical content and exhibits remarkable thermal stability. UV-visible difference spectra of the peptide-Co2+ complexes directly implicate thiols in metal coordination, and Co2+ d-d transitions in the visible range indicate that Co2+ is tetrahedrally coordinated. Mutant peptides containing conservative substitutions of one of the conserved His or either of the Cys residues displayed no significant Zn(2+)-induced conformational changes as monitored by CD and fluorescence spectra. We conclude that the N terminus of HIV-1 IN contains a metal-binding domain whose structure is stabilized by tetrahedral coordination of metal by histidines 12 and 16 and cysteines 40 and 43. A preliminary structural model for this zinc finger is presented.
...
PMID:Structural implications of spectroscopic characterization of a putative zinc finger peptide from HIV-1 integrase. 157 1

The nucleocapsid (NC) of human immunodeficiency virus type 1 consists of a large number of NC protein molecules, probably wrapping the dimeric RNA genome within the virion inner core. NC protein is a gag-encoded product that contains two zinc fingers flanked by basic residues. In human immunodeficiency virus type 1 virions, NCp15 is ultimately processed into NCp7 and p6 proteins. During virion assembly the retroviral NC protein is necessary for core formation and genomic RNA encapsidation, which are essential for virus infectivity. In vitro NCp15 activates viral RNA dimerization, a process most probably linked in vivo to genomic RNA packaging, and replication primer tRNA(Lys,3) annealing to the initiation site of reverse transcription. To characterize the domains of human immunodeficiency virus type 1 NC protein necessary for its various functions, the 72-amino acid NCp7 and several derived peptides were synthesized in a pure form. We show here that synthetic NCp7 with or without the two zinc fingers has the RNA annealing activities of NCp15. Further deletions of the N-terminal 12 and C-terminal 8 amino acids, leading to a 27-residue peptide lacking the finger domains, have little or no effect on NC protein activity in vitro. However deletion of short sequences containing basic residues flanking the first finger leads to a complete loss of NC protein activity. It is proposed that the basic residues and the zinc fingers cooperate to select and package the genomic RNA in vivo. Inhibition of the viral RNA binding and annealing activities associated with the basic residues flanking the first zinc finger of NC protein could therefore be used as a model for the design of antiviral agents.
...
PMID:Viral RNA annealing activities of human immunodeficiency virus type 1 nucleocapsid protein require only peptide domains outside the zinc fingers. 163 Nov 44

An 18-residue peptide (NC-F1) with an amino acid sequence corresponding to the N-terminal zinc finger of human immunodeficiency virus-1 nucleocapsid protein has been shown to bind to nucleic acids by fluorescence and NMR methods. Previously, this peptide has been shown to fold into a defined structure when bound to zinc (Summers et al., 1990). We have used a fluorescent polynucleotide, poly(ethenoadenylic acid), to monitor binding of this peptide to nucleic acids. In the presence of zinc, the peptide had a smaller site size (1.75 nucleotide residues/peptide) than in the absence of the metal ion (2.75). The salt sensitivity of the interaction indicated that two ion pairs are involved in the association of Zn2+ (NC-F1) with polynucleotide, whereas one ion pair is found in the metal-free peptide-nucleic acid complex. Competition experiments with single-stranded DNA (ss DNA) in either the presence or absence of Zn2+ showed that the peptide bound to ss DNA. Using NMR methods, we monitored the binding of a synthetic oligonucleotide, d(TTTGGTTT), to Zn(NC-F1). The hydrophobic residues F2 and I10, which are on the surface of the peptide and have been implicated in viral RNA recognition, were shown to interact with the oligomer. In accord with this observation, analysis of the salt dependence of the polynucleotide-peptide interaction indicates a nonelectrostatic component of about -6 kcal/mol, a value consistent with theoretical estimates of stacking energies of phenylalanine with nucleic acid bases.
...
PMID:Nucleic acid interactive properties of a peptide corresponding to the N-terminal zinc finger domain of HIV-1 nucleocapsid protein. 163 58

Human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) were purified by sucrose density gradient centrifugation in the presence of 1 mM EDTA. Pelleted gradient fractions were analyzed for total protein, total Gag capsid protein, and total zinc. Zinc was found to copurify and concentrate with the virus particles. Through successive cycles of resuspending in buffer containing EDTA and repelleting, the zinc content remained constant at about 1.7 mol of zinc per mol of Gag protein. Proteins from purified virus (HIV-1 and HTLV-I) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to polyvinylidene fluoride paper, and probed with 65ZnCl2. Viral nucleocapsid (NC) proteins (HIV-1 p7NC and HTLV-I p15NC) bound 65Zn2+. Other retroviruses, including simian immunodeficiency virus, equine infectious anemia virus, bovine leukemia virus, Moloney murine leukemia virus, mouse mammary tumor virus, and Mason-Pfizer monkey virus, were found to contain amounts of zinc per milligram of total protein similar to those found in HIV-1 and HTLV-I. Collectively, these data support the hypothesis that retroviral NC proteins function as zinc finger proteins in mature viruses.
...
PMID:Tightly bound zinc in human immunodeficiency virus type 1, human T-cell leukemia virus type I, and other retroviruses. 173 Nov 11

The nucleocapsid protein (NC) of the human immunodeficiency virus type 1 plays a crucial role in the formation of infectious viral particles and therefore should be a major target for the development of antiviral agents. This requires an investigation of NC protein structure and of its interactions with both primer tRNA(Lys,3) and genomic RNA. Nucleocapsid protein NCp7, which results from the maturation of NCp15, contains two zinc fingers flanked by sequences rich in basic and proline residues. Here we report the first synthesis of large quantities of NCp7 able to activate HIV-1 RNA dimerization and replication primer tRNA(Lys,3) annealing to the initiation site of reverse transcription. In addition UV spectroscopic analyses performed to characterize the Co2+ binding properties of each zinc finger suggest that the two fingers probably interact in NCp7.
...
PMID:First large scale chemical synthesis of the 72 amino acid HIV-1 nucleocapsid protein NCp7 in an active form. 195 5

A variety of cellular proteins have been found to bind to related DNA sequences in the enhancer elements of the human immunodeficiency virus, the kappa immunoglobulin gene, the class I major histocompatibility complex gene, and the beta-interferon gene. Recently, lambda gt11 gene expression cloning using ligated oligonucleotide probes complementary to these DNA binding motifs has been performed. An identical cDNA clone encoding a cellular protein, referred to as HIV-EP1, MBP-1, or PRDII-BF1, that binds to each of these sequences has been identified. This cDNA potentially encodes a 298-kDa cellular protein with two widely separated zinc finger binding domains, each of which binds to the same DNA sequence. As part of an effort to examine the chromosomal organization of cellular genes encoding transcription factors, we report the chromosomal mapping of the gene encoding this zinc finger protein (ZNF40) to chromosome 6p22.3-24.
...
PMID:Localization of the zinc finger DNA-binding protein HIV-EP1/MBP-1/PRDII-BF1 to human chromosome 6p22.3-p24. 203

To identify RNA and protein sequences involved in packaging of human immunodeficiency virus type 1 (HIV-1), various mutations were introduced into the viral genome. Portions of the human immunodeficiency virus type 1 genome between the first splice donor site and the gag initiation codon were deleted to investigate the RNA packaging site (psi). Point mutations that alter cysteine residues in one or both zinc finger motifs of p7, a cleavage product of the gag precursor, were created to study the role of the gag zinc fingers in packaging. The psi site mutants and the gag mutants exhibited similar phenotypes. Cells transfected with the mutant genomes, while expressing normal levels of human immunodeficiency virus type 1 RNA and proteins, produced viral particles that were normal in protein content but lacked detectable viral RNA. These mutant virions were unable to productively infect cells. The combination of human immunodeficiency virus type 1 packaging mutations should minimize fortuitous assembly of infectious virus and may provide a means to produce noninfectious particles for candidate vaccines.
...
PMID:Mutations of RNA and protein sequences involved in human immunodeficiency virus type 1 packaging result in production of noninfectious virus. 210 98

1 2 3 4 5 6 7 8 9 10 Next >>