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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The alternatively spliced 290-nucleotide NS2-specific exon of the
parvovirus
minute virus of mice (MVM), which is flanked by a large intron upstream and a small intron downstream, constitutively appears both in the R1 mRNA as part of a large 5'-terminal exon (where it is translated in open reading frame 3 [ORF3]), and in the R2 mRNA as an internal exon (where it is translated in ORF2). We have identified a novel bipartite exon enhancer element, composed of CA-rich and purine-rich elements within the 5' and 3' regions of the exon, respectively, that is required to include NS2-specific exon sequences in mature spliced mRNA in vivo. These two compositionally different enhancer elements are somewhat redundant in function: either element alone can at least partially support exon inclusion. They are also interchangeable: either element can function at either position. Either a strong 3' splice site upstream (i.e., the exon 5' terminus) or a strong 5' splice site downstream (i.e., the exon 3' terminus) is sufficient to prevent skipping of the NS2-specific exon, and a functional upstream 3' splice site is required for inclusion of the NS2-specific exon as an internal exon into the mature, doubly spliced R2 mRNA. The bipartite enhancer functionally strengthens these termini: the requirement for both the CA-rich and purine-rich elements can be overcome by improvements to the polypyrimidine tract of the upstream intron 3' splice site, and the purine-rich element also supports exon inclusion mediated through the downstream 5' splice sites. In summary, a suboptimal large-intron polypyrimidine tract, sequences within the downstream small intron, and a novel bipartite exonic enhancer operate together to yield the balanced levels of R1 and R2 observed in vivo. We suggest that the unusual bipartite exonic enhancer functions to mediate proper levels of inclusion of the NS2-specific exon in both singly spliced R1 and doubly spliced R2.
Mol
Cell Biol 1999 Jan
PMID:CA- and purine-rich elements form a novel bipartite exon enhancer which governs inclusion of the minute virus of mice NS2-specific exon in both singly and doubly spliced mRNAs. 985 60
Background: The 5;-->3;-exonuclease activity of Thermus aquaticus (Taq) DNA polymerase permits polymerase chain reaction (PCR) product detection immediately after amplification using a fluorogenic probe. This approach eliminates the requirement for gel electrophoresis or enzyme immunoassays (EIA). The ligonucleotide probe is labeled with a reporter dye at its 5' terminus and a quencher dye at its 3' terminus and is present during DNA amplification. The exonuclease cleaves the reporter molecule from the probe-template hybrid, releasing it from the influence of the quencher molecule. The result is an increase in reporter fluorescence that can be read directly in a fluorescence spectormeter. In contrast to time-consuming gel electrophoresis and Southern blot hybridization or an EIA, this method can produce results from an entire 96-well microtiter plate in 15 minutes. Methods and Results: A B19-specific fluorogenic probe was synthesized containing a 5'-FAM label and a 3'-TAMRA label. Thirty clinical samples were analyzed for Human
parvovirus
B19 DNA by PCR amplification using both the fluorogenic and EIA method. Conclusions: Results generated with the fluorogenic probe correlated perfectly with those of the EIA, and the method would be particularly useful for high-volume work loads where gel or EIA-based approaches would be cumbersome.
Mol
Diagn 1996 Dec
PMID:Exonuclease-released Fluorescence Detection of Human Parvovirus B19 DNA. 1046 79
Initially recognized as a HeLa factor essential for
parvovirus
DNA replication,
parvovirus
initiation factor (PIF) is a site-specific DNA-binding complex consisting of p96 and p79 subunits. We have cloned and sequenced the human cDNAs encoding each subunit and characterized their products expressed from recombinant baculoviruses. The p96 and p79 polypeptides have 40% amino acid identity, focused particularly within a 94-residue region containing the sequence KDWK. This motif, first described for the Drosophila homeobox activator DEAF-1, identifies an emerging group of metazoan transcriptional modulators. During viral replication, PIF critically regulates the viral nickase, but in the host cell it probably modulates transcription, since each subunit is active in promoter activation assays and the complex binds to previously described regulatory elements in the tyrosine aminotransferase and transferrin receptor promoters. Within its recognition site, PIF binds coordinately to two copies of the tetranucleotide PuCGPy, which, remarkably, can be spaced from 1 to 15 nucleotides apart, a novel flexibility that we suggest may be characteristic of the KDWK family. Such tetranucleotides are common in promoter regions, particularly in activating transcription factor/cyclic AMP response element-binding protein (ATF/CREB) and E-box motifs, suggesting that PIF may modulate the transcription of many genes.
Mol
Cell Biol 1999 Nov
PMID:Two new members of the emerging KDWK family of combinatorial transcription modulators bind as a heterodimer to flexibly spaced PuCGPy half-sites. 1052 63
Adeno-associated virus (AAV), a non-pathogenic human
parvovirus
, is gaining attention for its potential use as a human gene therapy vector. One of the most attractive features of recombinant AAV vectors is the ability to be stably maintained in host cells as integrated proviruses. This property is particularly desireable for therapies requiring long-term correction of a genetic defect. This review highlights recent advances made in the AAV field and will discuss some limitations of rAAV vector integration. A novel method for enhancing the integration efficiency of these vectors will be presented.
Int J
Mol
Med 2000 Jul
PMID:Adeno-associated viral vectors as gene delivery vehicles. 1085 Dec 61
Canine
parvovirus
(CPV) emerged in 1978 as a host range variant of feline panleukopenia virus (FPV). This change of host was mediated by the mutation of five residues on the surface of the capsid. CPV and FPV enter cells by endocytosis and can be taken up by many non-permissive cell lines, showing that their host range and tissue specificity are largely determined by events occurring after cell entry. We have determined the structures of a variety of strains of CPV and FPV at various pH values and in the presence or absence of Ca(2+). The largest structural difference was found to occur in a flexible surface loop, consisting of residues 359 to 375 of the capsid protein. This loop binds a divalent calcium ion in FPV and is adjacent to a double Ca(2+)-binding site, both in CPV and FPV. Residues within the loop and those associated with the double Ca(2+)-binding site were found to be essential for virus infectivity. The residues involved in the double Ca(2+)-binding site are conserved only in FPV and CPV. Our results show that the loop conformation and the associated Ca(2+)-binding are influenced by the Ca(2+) concentration, as well as pH. These changes are correlated with the ability of the virus to hemagglutinate erythrocytes. The co-localization of hemagglutinating activity and host range determinants on the virus surface implies that these properties may be functionally linked. We speculate that the flexible loop and surrounding regions are involved in binding an as yet unidentified host molecule and that this interaction influences host range.
J
Mol
Biol 2000 Jul 14
PMID:Host range and variability of calcium binding by surface loops in the capsids of canine and feline parvoviruses. 1088 55
Adeno-associated virus (AAV), a defective
parvovirus
, was discovered more than 30 years ago. Interest in this virus for human gene therapy applications focuses on its non-pathogenicity, broad tropism and infectivity, site-specific integration and long-term persistence. The field of rAAV research has considerably advanced: titers of 1014 p/ml have been achieved, plasmid systems devised to produce helper-free viruses, chimaeric vectors combining properties of rAAV ITRs and large sequence capacity from Ad/HS vectors in parallel with the revolutionary intron strategy based on heterodimerisation of the forming concatamers have expanded the vector capacity. Muscle cells and neurons (post-mitotic cells) are amongst the most efficient targets of rAAV delivery and AAV receptors and co-receptors have been identified. This review will describe advances in the field of rAAV technology that overcome certain limitations of the vector as a gene delivery system and overview applications involving these recombinant vectors for the treatment of acquired and inherited diseases.
Int J
Mol
Med 2000 Oct
PMID:Gene therapy vectors based on adeno-associated virus: characteristics and applications to acquired and inherited diseases (review). 1099 27
The non-structural protein NS1, encoded by the
parvovirus
minute virus of mice (MVM), is a potent regulator of viral gene expression in addition to prominent roles in viral replication and cytopathic effects associated with parvoviral infection. Although NS1 involves the modulation of viral and cellular transcription, the primary activation mechanism of MVM NS1 remains unclear. In the present study, we show here that the coactivator CREB binding protein, CBP, could potentiate NS1-mediated transcription as measured on the P38 promoter, which drives expression of the MVM capsid genes. NS1 bound to the two related cysteine-histidine-rich regions of CBP, referred to as C/H1 and C/H3, the former of which has an antagonistic function to CBP upon the NS1-transactivation. Furthermore, NS1 inhibited the synergistic transactivation by CBP and p53. These findings suggested that CBP as a transcriptional coactivator is required for NS1-mediated viral and cellular transcription in
parvovirus
-infected cells, resulting in cell proliferation and differentiation to achieve its lytic cycle.
Int J
Mol
Med 2001 Jan
PMID:Effects of interaction between parvovirus minute virus of mice NS1 and coactivator CBP on NS1- and p53-transactivation. 1111 8
Adeno-associated virus (AAV) is a ubiquitous human helper-dependent
parvovirus
which may interact with human papillomaviruses (HPV) to modify a woman's risk of cervical neoplasia. This analysis was nested in a cohort study of low-income women receiving Pap smears as part of their family planning services. We selected cases (55 with high-grade cervical squamous intraepithelial lesions (HSIL) and 162 with low-grade LSIL) and controls (96 women with normal cervical cytology) and analyzed cervical DNA for AAV, using PCR amplification/dot blot hybridization, and HPV, using hybrid capture I. AAV positivity was associated with a significantly reduced risk of HSIL (age and HPV-adjusted odds ratio (aOR) = 0.32) yet not with LSIL (aOR = 0.78); 53.8% of HSIL, 66.9% of LSIL, and 70.7% of controls were AAV+. AAV appears to interact with HPV to reduce SIL risk; relative to the HPV-/AAV+ exposure, the respective aORs for HSIL and HPV+/AAV-, HPV+/AAV+, and HPV-/AAV+ were 17.0, 6.9, and 3.5. AAV+ was not associated with age, race, HPV status, or sexual or reproductive risk factors. These results strongly suggest that AAV may play a protective or inhibitory role in late stage cervical carcinogenesis. This conclusion needs to be verified in additional epidemiologic studies.
Exp
Mol
Pathol 2001 Apr
PMID:Adeno-associated virus is associated with a lower risk of high-grade cervical neoplasia. 1126 51
Adeno-associated virus 2 (AAV), a nonpathogenic human
parvovirus
, has gained attention as a potentially useful vector for human gene therapy. Here, we report successful AAV-mediated stable transduction and high-efficiency, long-term, erythroid lineage-restricted expression of a human beta-globin gene in primary murine hematopoietic stem cells in vivo. Bone marrow-derived primitive Sca-1(+), lin(-) hematopoietic stem cells from homozygous beta-thalassemic mice were transduced ex vivo with a recombinant AAV vector containing a normal human beta-globin gene followed by transplantation into low-dose-irradiated B6.c-kitW(41/41) anemic recipient mice. Six months posttransplantation, tail-vein blood samples were analyzed by PCR amplification to document the presence of the transduced human beta-globin gene sequences in the peripheral blood cells. Semiquantitative PCR analyses revealed that the transduced human beta-globin gene sequences were present at approximately 1 copy per cell. The efficiency of the human beta-globin gene expression was determined to be up to 35% compared with the murine endogenous beta-globin gene by semiquantitative RT-PCR analyses. Peripheral blood samples from several positive recipient mice obtained 10 months posttransplantation were fractionated to obtain enriched populations of granulocytes, lymphocytes, and erythroid cells. PCR analyses revealed the presence of the human beta-globin gene sequences in granulocytes and lymphocytes, indicating multilineage reconstitution. However, only the erythroid population was positive following RT-PCR analyses, suggesting lineage-restricted expression of the transduced human beta-globin gene. Southern blot analyses of total genomic DNA samples isolated from bone marrow cells from transplanted mice also documented proviral integration. These results provide further support for the potential use of recombinant AAV vectors in gene therapy of beta-thalassemia and sickle-cell disease.
Mol
Ther 2001 Jun
PMID:Adeno-associated virus 2-mediated transduction and erythroid lineage-restricted long-term expression of the human beta-globin gene in hematopoietic cells from homozygous beta-thalassemic mice. 1140 8
The human
parvovirus
adeno-associated virus type 2 (AAV-2) possesses many features that make it an attractive vector for gene delivery in vivo. However, its broad host range may limit its usefulness and effectivity in several gene therapy applications in which transgene expression needs to be limited to a specific organ or cell type. In this study, we explored the possibility of directing recombinant AAV-2 transduction by incorporating targeting peptides previously isolated by in vivo phage display. Two putative loops within the AAV-2 capsid were examined as sites for incorporation of peptides. We tested the effects of deleting these loops and different strategies for the incorporation of several targeting peptides. The tumor-targeting sequence NGRAHA and a Myc epitope control were incorporated either as insertions or as replacements of the original capsid sequence. Viruses were assessed for packaging, accessibility of incorporated peptides, heparin binding, and transduction in a range of cell lines. Whereas recombinant viruses containing mutant capsid proteins were produced efficiently, transduction of several cell lines was significantly impaired for most modifications. However, certain mutants containing the peptide motif NGR, which binds CD13 (a receptor expressed in angiogenic vasculature and in many tumor cell lines), displayed an altered tropism toward cells expressing this receptor. Based on this work and previous studies, possible strategies for achieving in vivo targeting of recombinant AAV-2 are discussed.
Mol
Ther 2001 Jun
PMID:Incorporation of tumor-targeting peptides into recombinant adeno-associated virus capsids. 1140 11
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