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1.
Mod Pathol ; 14(11): 1073-8, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11706066

ABSTRACT

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric repeats onto chromosomal ends using a segment of its RNA component as a template. Its activity has become an established indicator of the diagnosis, biological behavior, and prognosis of several tumors. However, few studies have investigated the diagnostic and prognostic importance of the expression of telomerase catalytic subunit (hTERT) mRNA in transitional cell carcinoma of the upper urinary tract (TCC-UUT). We investigated the expression of hTERT mRNA using in situ hybridization in 125 cases of TCC-UUT, and also its relation with the expression of telomerase RNA component (hTERC), proliferating cell nuclear antigen (PCNA) immunoreactivity, clinicopathologic parameters, and clinical outcome. A positive expression of hTERT mRNA was recognized in 93.6% of the samples and was apparent within the cytoplasm of tumor cells. In the normal urothelium examined in a few cases, its expression was barely detected. hTERT mRNA scores showed a significant association with hTERC score. However, no relationship was found between the expression of hTERT mRNA and clinicopathologic findings, PCNA index, or prognosis. These results suggest that the expression of hTERT mRNA does not predict prognosis in TCC-UUT.


Subject(s)
Carcinoma, Transitional Cell/pathology , RNA, Messenger/metabolism , Telomerase/genetics , Ureteral Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Carcinoma, Transitional Cell/genetics , Carcinoma, Transitional Cell/metabolism , Catalytic Domain , DNA-Binding Proteins , Female , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , In Situ Hybridization , Male , Middle Aged , Neoplasm Staging , Predictive Value of Tests , Prognosis , Proliferating Cell Nuclear Antigen/analysis , RNA, Messenger/genetics , Survival Analysis , Ureteral Neoplasms/genetics , Ureteral Neoplasms/metabolism
2.
J Virol ; 75(16): 7321-9, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11462004

ABSTRACT

A DNA-binding domain (DBD) was identified on simian virus 40 (SV40) major capsid protein Vp1, and the domain's function in the SV40 life cycle was examined. The DBD was mapped by assaying various recombinant Vp1 proteins for DNA binding in vitro. The carboxy-terminal 58-residue truncated Vp1DeltaC58 pentamer bound DNA with a K(d) of 1.8 x 10(-9) M in terms of the protein pentamer, while full-length Vp1 and carboxy-terminal-17-truncated Vp1DeltaC17 had comparable apparent K(d)s of 5.3 x 10(-9) to 7.3 x 10(-9) M in terms of the protein monomers. Previously identified on Vp1 was a nuclear localization signal (NLS) consisting of two N-terminal basic clusters, NLS1 (4-KRK-6) and NLS2 (15-KKPK-18). Vp1DeltaC58 pentamers harboring multiple-point mutations in NLS1 (NLSm1), NLS2 (NLSm2), or both basic clusters (NLSm1. 2) had progressively decreased DNA-binding activity, down to 0.7% of the Vp1DeltaC58 level for NLSm1. 2 Vp1. These data, along with those of N-terminally truncated proteins, placed the DBD in overlap with the bipartite NLS. The role of the Vp1 DBD during infection was investigated by taking advantage of NLS phenotypic complementation (N. Ishii, A. Nakanishi, M. Yamada, M. H. Macalalad, and H. Kasamatsu, J. Virol. 68:8209-8216, 1994), in which an NLS-defective Vp1 could localize to the nucleus in the presence of wild-type minor capsid proteins Vp2 and Vp3. This approach made it possible to dissect the role of the bifunctional Vp1 NLS-DBD in virion assembly in the nucleus. Mutants of the viable nonoverlapping SV40 (NO-SV40) DNA NLSm1, NLSm2, and NLSm1. 2 replicated normally following transfection into host cells and produced capsid proteins at normal levels. All mutant Vp1s were able to interact with Vp3 in vitro. The mutants NLSm1 and NLSm1. 2 were nonviable, and the mutant Vp1s unexpectedly failed to localize to the nucleus though Vp2 and Vp3 did, suggesting that the mutated NLS1 acted as a dominant signal for the cytoplasmic localization of Vp1. Mutant NLSm2, for which the mutant Vp1's nuclear localization defect was complemented by Vp2 and Vp3, displayed a 5,000-fold reduced viability. Analysis of NLSm2 DNA-transfected cell lysate revealed a 10-fold reduction in the level of DNase I-protected viral DNA, and yet virion-like particles were found among the DNase I-resistant material. Collective results support a role for Vp1 NLS2-DBD2 in the assembly of virion particles. The results also suggest that this determinant can function in the infection of new cells.


Subject(s)
Capsid Proteins , Capsid/physiology , Simian virus 40/physiology , Virus Assembly , Animals , Mutation , Recombinant Proteins/genetics
3.
J Am Assoc Gynecol Laparosc ; 8(2): 295-8, 2001 May.
Article in English | MEDLINE | ID: mdl-11342741

ABSTRACT

A 7-year-old girl was admitted to our hospital because of sudden lower abdominal pain and vomiting. Emergency laparoscopy and cystectomy were performed, with a diagnosis of torsion of an ovarian cyst. All manipulations were possible through a 2-cm incision in the abdominal wall.


Subject(s)
Laparoscopy , Ovarian Neoplasms/surgery , Teratoma/surgery , Abdominal Pain/etiology , Child , Female , Humans , Ovarian Neoplasms/complications , Teratoma/complications , Torsion Abnormality
4.
Mod Pathol ; 14(5): 371-6, 2001 May.
Article in English | MEDLINE | ID: mdl-11353044

ABSTRACT

The expression of p27(Kip1), a negative regulator of the cell cycle, has been reported to correlate with the biological behavior and prognosis of several tumors. However, its prognostic importance in transitional cell carcinoma of the upper urinary tract (TCC-UUT) has not previously been investigated. We investigated p27(Kip1) protein expression using immunohistochemistry in 132 cases of TCC-UUT and also its relation to proliferating cell nuclear antigen (PCNA) immunoreactivity, p53 oncoprotein immunoreactivity, clinicopathologic parameters, and clinical outcome. A positive expression of p27(Kip1) protein was recognized in 94.7% of the samples and was apparent within tumor nuclei. In the normal urothelium, its expression was identified in all cell layers. A positive expression of p53 oncoprotein was recognized in 27.2% of the patients. The PCNA index was 7.4 to 93.1% (mean, 66.4%). Examination of the relationships between the expression of p27(Kip1) protein and clinicopathologic findings, PCNA index, and the expression of p53 oncoprotein revealed that the expression of p27(Kip1) protein decreased significantly with stage and grade. In a univariate analysis of disease-free and overall survival rates, no correlation was found between the expression of p27(Kip1) protein and prognosis. The expression of p27(Kip1) protein appears to be of little or no value in informing the prognosis in TCC-UUT.


Subject(s)
Carcinoma, Transitional Cell/metabolism , Cell Cycle Proteins , Cyclin-Dependent Kinases/antagonists & inhibitors , Genes, Tumor Suppressor , Microtubule-Associated Proteins/metabolism , Tumor Suppressor Proteins , Urologic Neoplasms/metabolism , Adult , Aged , Aged, 80 and over , Carcinoma, Transitional Cell/mortality , Carcinoma, Transitional Cell/secondary , Carcinoma, Transitional Cell/surgery , Cell Count , Cell Nucleus/metabolism , Cell Nucleus/pathology , Cyclin-Dependent Kinase Inhibitor p27 , Humans , Immunohistochemistry , Middle Aged , Neoplasm Recurrence, Local , Proliferating Cell Nuclear Antigen/metabolism , Survival Analysis , Treatment Outcome , Tumor Suppressor Protein p53/metabolism , Urologic Neoplasms/mortality , Urologic Neoplasms/pathology , Urologic Neoplasms/surgery , Urothelium/cytology , Urothelium/metabolism , Urothelium/pathology
5.
Arch Gynecol Obstet ; 264(4): 218-9, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11205714

ABSTRACT

A 32-year-old nulligravida was hospitalized because of preterm labor and treated with intravenous ritodrine hydrochloride. After 33 days of therapy, the patient developed a fine maculopapular rash.


Subject(s)
Erythema/chemically induced , Ritodrine/adverse effects , Tocolytic Agents/adverse effects , Adrenergic beta-Agonists/adverse effects , Adult , Female , Humans , Obstetric Labor, Premature/drug therapy , Pregnancy
6.
J Am Assoc Gynecol Laparosc ; 8(1): 159-60, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11172134

ABSTRACT

A 48-year-old woman was seen because of an abdominal tumor. Laparoscopy was performed for diagnosis and treatment. A large cystic mass was hanging from the anterior abdominal wall and was removed with laparoscopic assistance. Histologic examination revealed a urachal cyst. (J Am Assoc Gynecol Laparosc 8(1):159-160, 2001)


Subject(s)
Laparoscopy , Urachal Cyst/surgery , Female , Humans , Middle Aged , Urachal Cyst/pathology
7.
J Virol ; 74(23): 11388-93, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11070039

ABSTRACT

We have developed a new nonoverlapping infectious viral genome (NO-SV40) in order to facilitate structure-based analysis of the simian virus 40 (SV40) life cycle. We first tested the role of cysteine residues in the formation of infectious virions by individually mutating the seven cysteines in the major capsid protein, Vp1. All seven cysteine mutants-C9A, C49A, C87A, C104A, C207S, C254A, and C267L-retained viability. In the crystal structure of SV40, disulfide bridges are formed between certain Cys104 residues on neighboring pentamers. However, our results show that none of these disulfide bonds are required for virion infectivity in culture. We also introduced five different mutations into Cys254, the most strictly conserved cysteine across the polyomavirus family. We found that C254L, C254S, C254G, C254Q, and C254R mutants all showed greatly reduced (around 100,000-fold) plaque-forming ability. These mutants had no apparent defect in viral DNA replication. Mutant Vp1's, as well as wild-type Vp2/3, were mostly localized in the nucleus. Further analysis of the C254L mutant revealed that the mutant Vp1 was able to form pentamers in vitro. DNase I-resistant virion-like particles were present in NO-SV40-C254L-transfected cell lysate, but at about 1/18 the amount in wild-type-transfected lysate. An examination of the three-dimensional structure reveals that Cys254 is buried near the surface of Vp1, so that it cannot form disulfide bonds, and is not involved in intrapentamer interactions, consistent with the normal pentamer formation by the C254L mutant. It is, however, located at a critical junction between three pentamers, on a conserved loop (G2H) that packs against the dual interpentamer Ca(2+)-binding sites and the invading C-terminal helix of an adjacent pentamer. The substitution by the larger side chains is predicted to cause a localized shift in the G2H loop, which may disrupt Ca(2+) ion coordination and the packing of the invading helix, consistent with the defect in virion assembly. Our experimental system thus allows dissection of structure-function relationships during the distinct steps of the SV40 life cycle.


Subject(s)
Capsid/chemistry , Cysteine/physiology , Simian virus 40/chemistry , Capsid/analysis , Capsid/physiology , Capsid Proteins , DNA Replication , Mutation , Protein Structure, Secondary , Simian virus 40/pathogenicity , Structure-Activity Relationship , Virion/physiology
8.
J Am Assoc Gynecol Laparosc ; 7(2): 255-6, 2000 May.
Article in English | MEDLINE | ID: mdl-10806273

ABSTRACT

Patients with ectopic pregnancy complicated by heavy hemoperitoneum generally undergo immediate laparotomy, and homologous blood transfusion is sometimes started before the operation. Two women underwent laparoscopic surgery for heavy hemoperitoneum (2600 and 1900 ml) due to ectopic pregnancy. The aspirated blood was reinfused during operation through a leukocyte-reduction filter after lavage with an autologous blood-salvage transfusion apparatus.


Subject(s)
Blood Transfusion, Autologous/methods , Hemoperitoneum/etiology , Hemoperitoneum/surgery , Laparoscopy/methods , Pregnancy, Tubal/surgery , Adult , Emergencies , Female , Humans , Intraoperative Period , Pregnancy
9.
Hum Pathol ; 31(2): 193-200, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10685633

ABSTRACT

Tumor cell invasion and metastasis are biologically dependent on the proteolytic destruction of surrounding matrix components. Matrix metalloproteinase-2 (MMP-2) is able to cleave type IV collagen, and membrane-type-1-matrix metalloproteinase (MT1-MMP) induces activation of proMMP-2. We investigated the expression of MMP-2 and MT1-MMP using in situ hybridization and immunohistochemistry in 102 cases of transitional cell carcinoma of the upper urinary tract (TCC-UUT). A positive expression of each metalloproteinase was recognized in all samples and was apparent within the cytoplasm of tumor epithelial cells and/or stromal cells situated at the interface between tumor and stroma. Our analysis of clinicopathologic findings showed a relationship between MMP-2 and MT1-MMP expression and stage. The correlation between the MMP-2 protein staining score for tumor epithelial cells and overall survival rate reached significance in the univariate analysis. However, only stage was associated with disease-free and overall survivals in the multivariate analysis. In conclusion, the detection of MMP-2 and MT1-MMP would appear to be of limited value in informing the prognosis of TCC-UUT.


Subject(s)
Carcinoma, Transitional Cell/genetics , Gene Expression , Matrix Metalloproteinase 2/genetics , Matrix Metalloproteinases/genetics , Metalloendopeptidases , Urologic Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Carcinoma, Transitional Cell/chemistry , Carcinoma, Transitional Cell/mortality , Disease-Free Survival , Female , Humans , Immunohistochemistry , In Situ Hybridization , Male , Matrix Metalloproteinase 2/analysis , Matrix Metalloproteinases/analysis , Matrix Metalloproteinases, Membrane-Associated , Middle Aged , RNA, Messenger/analysis , Survival Rate , Urologic Neoplasms/chemistry , Urologic Neoplasms/mortality
10.
J Am Assoc Gynecol Laparosc ; 7(1): 161-2, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10648760

ABSTRACT

Ectopic pregnancy is one complication of tubal sterilization. A 39-year-old multiparous woman underwent puerperal transcutaneous tubal ligation in the infraumbilical region after delivery of her fourth child. Tubal pregnancy occurred in the right and left salpinx, respectively, at different times, with laparoscopic surgery performed after each one.


Subject(s)
Postoperative Complications/etiology , Pregnancy, Tubal/etiology , Sterilization, Tubal , Adult , Female , Humans , Laparoscopy , Parity , Pregnancy , Pregnancy, Tubal/surgery
11.
Acta Obstet Gynecol Scand ; 79(10): 830-3, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11304964

ABSTRACT

OBJECTIVE: Our purpose was to find factors that may help increase the number of the HSC (CD34+) collected from umbilical cord blood for transplantation. STUDY DESIGN: We assessed the effect of cesarean sections and vaginal deliveries on the volume of the umbilical cord blood collected from 155 healthy term neonates retrospectively. RESULTS: The volume of umbilical cord blood obtained in 29 cesarean deliveries was 103.9 +/- 33.6 ml compared with 84.2 +/- 25.3 ml collected in 126 vaginal deliveries. Although the percentage of CD34+ cells was comparable in both groups, the absolute number of CD34+ cells was significantly higher in the cesarean section group because of the larger volume collected. CONCLUSIONS: Cesarean sections may allow collection of significantly increased volumes of umbilical cord blood and numbers of CD34+ cells compared to vaginal deliveries.


Subject(s)
Antigens, CD34/analysis , Blood Volume/physiology , Fetal Blood/cytology , Adult , Blood Specimen Collection , Cesarean Section , Female , Fetal Blood/immunology , Flow Cytometry , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/immunology , Humans , Infant, Newborn , Pregnancy , Retrospective Studies
12.
Obstet Gynecol ; 94(5 Pt 2): 822-3, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10546742

ABSTRACT

BACKGROUND: Moyamoya disease with pregnancy is rare and might present with cerebral hemorrhage. CASE: A 22-year-old primigravida suddenly developed muscular weakness in the right arm and facial discomfort 3 days after cesarean. Computed tomography and cerebrovascular angiography found cerebral infarction attributable to moyamoya disease. Bilateral anastomosis of superficial temporal and middle cerebral arteries was done. CONCLUSION: Moyamoya disease with pregnancy might present as cerebral infarction after cesarean.


Subject(s)
Cerebral Infarction/etiology , Cesarean Section , Moyamoya Disease/complications , Moyamoya Disease/diagnosis , Postoperative Complications/etiology , Adult , Female , Humans , Pregnancy
13.
Proc Natl Acad Sci U S A ; 96(1): 238-41, 1999 Jan 05.
Article in English | MEDLINE | ID: mdl-9874802

ABSTRACT

The viability of boron neutron capture therapy depends on the development of tumor-targeting agents that contain large numbers of boron-10 (10B) atoms and are readily taken up by cells. Here we report on the selective uptake of homogeneous fluorescein-labeled nido-carboranyl oligomeric phosphate diesters (nido-OPDs) by the cell nucleus and their long-term retention after their delivery into the cytoplasm of TC7 cells by microinjection. All nido-OPDs accumulated in the cell nucleus within 2 h after microinjection. However, nido-OPDs in which the carborane cage was located on a side chain attached to the oligomeric backbone were redistributed between both the cytoplasm and nucleus after 24 h of incubation, whereas nido-OPDs in which the carborane cage was located along the oligomeric backbone remained primarily in the nucleus. Furthermore, cell-free incubation of digitonin-permeabilized TC7 cells with the nido-OPDs resulted in nuclear accumulation of the compounds, thus corroborating the microinjection studies. Our observation of fluorescence primarily located in the cell nucleus indicates that nuclear-specific uptake of sufficient amounts of 10B for effective boron neutron capture therapy ( approximately 10(8)-10(9) 10B atoms/tumor cell) via nido-OPDs is achievable.


Subject(s)
Boron Compounds/metabolism , Boron Neutron Capture Therapy , Cell Nucleus/metabolism , Organophosphates/metabolism , Biological Transport , Cell Compartmentation , Cytoplasm/metabolism , Fluoresceins/metabolism , Microinjections , Neoplasms/therapy
14.
Radiat Med ; 16(2): 99-107, 1998.
Article in English | MEDLINE | ID: mdl-9650896

ABSTRACT

Eight subjects were examined both by abdominal X-ray computed transverse axial tomography (CT) and magnetic resonance imaging (MRI) (SE) (TR/TE, 200 ms/15 ms); another eight volunteers were subjected to three MRI scans to test the reliability of repeated measures. Correlations between fat area measures obtained by CT and by MRI for subcutaneous fat, total fat, and visceral vs. subcutaneous-fat ratio were highly significant (r = 0.93, 0.91, and 0.94, respectively; p < 0.01), and the standard errors of estimation were 9.99, 23.87, and 0.0047. The average errors of the method for different fat areas were 2.20 cm2 (intra-examination variance) and 3.75 cm2 (inter-examination variance) for visceral and 0.82 cm2 (intra-examination variance) and 1.29 cm2 (inter-examination variance) for subcutaneous fat areas, respectively. These results suggest that SE MRI is a practical approach to evaluate body fat distribution without the exposure to radiation. The reproducibility of SE MRI for the determination of fat areas is high; variation is small and acceptable. However, it is difficult to determine which estimate of fat area should be accepted when there is a discrepancy between MRI and CT measures.


Subject(s)
Adipose Tissue/pathology , Magnetic Resonance Imaging/methods , Obesity/diagnosis , Radiography, Abdominal , Tomography, X-Ray Computed/methods , Adipose Tissue/diagnostic imaging , Adipose Tissue/metabolism , Adult , Female , Humans , Male , Middle Aged , Obesity/metabolism , Reproducibility of Results
15.
J Mol Biol ; 275(2): 187-95, 1998 Jan 16.
Article in English | MEDLINE | ID: mdl-9466902

ABSTRACT

Chromatin structure and protein-protein interactions play an important role in eukaryotic gene function. Nucleosomal rearrangement at the simian virus 40 (SV40) regulatory region occurs at the late stages of the viral life cycle preceding viral assembly. The SV40 capsid proteins are required for this nucleosomal rearrangement suggesting that they participate in turning-off the viral promoters. In aiming to elucidate the role of the capsid proteins in gene regulation, we studied the interaction between VP3, an internal capsid protein, and the cellular transcription factor Sp1, a major regulator of both the early and late viral promoters. Our results showed that VP3 repressed transcription from the viral early promoter in vitro. We found significant cooperativity between Sp1 and VP3 in specific DNA-binding to the Sp1 binding site. In addition, protein-protein interactions between VP3 and Sp1 in the absence of DNA were observed. These findings have led us to conclude that the novel host-viral Sp1-VP3 complex down regulates viral transcription and further suggest that Sp1 participates in recruiting VP3 to the SV40 minichromosome in SV40 assembly.


Subject(s)
Capsid Proteins , Capsid/metabolism , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Viral , Promoter Regions, Genetic , Simian virus 40/physiology , Sp1 Transcription Factor/metabolism , Base Sequence , HeLa Cells , Humans , Nucleosomes/physiology , Oligonucleotide Probes , Polymerase Chain Reaction , Regulatory Sequences, Nucleic Acid , Simian virus 40/genetics
16.
Annu Rev Microbiol ; 52: 627-86, 1998.
Article in English | MEDLINE | ID: mdl-9891810

ABSTRACT

Genome and pre-genome replication in all animal DNA viruses except poxviruses occurs in the cell nucleus (Table 1). In order to reproduce, an infecting virion enters the cell and traverses through the cytoplasm toward the nucleus. Using the cell's own nuclear import machinery, the viral genome then enters the nucleus through the nuclear pore complex. Targeting of the infecting virion or viral genome to the multiplication site is therefore an essential process in productive viral infection as well as in latent infection and transformation. Yet little is known about how infecting genomes of animal DNA viruses reach the nucleus in order to reproduce. Moreover, this nuclear locus for viral multiplication is remarkable in that the sizes and composition of the infectious particles vary enormously. In this article, we discuss virion structure, life cycle to reproduce infectious particles, viral protein's nuclear import signal, and viral genome nuclear targeting.


Subject(s)
Cell Nucleus/virology , DNA Replication , DNA, Viral/physiology , Virus Replication/genetics , Adenoviridae/genetics , Adenoviridae/physiology , Animals , DNA, Viral/genetics , Hepadnaviridae/genetics , Hepadnaviridae/physiology , Herpesvirus 1, Human/genetics , Herpesvirus 1, Human/physiology , Humans , Papillomaviridae/genetics , Papillomaviridae/physiology , Parvovirus/genetics , Parvovirus/physiology , Polyomavirus/genetics , Polyomavirus/physiology , Simian virus 40/genetics , Viral Proteins/genetics , Viral Proteins/physiology , Virion/chemistry , Virion/physiology
18.
Trends Cell Biol ; 6(5): 189-95, 1996 May.
Article in English | MEDLINE | ID: mdl-15157471

ABSTRACT

Import o f viral DNA into the nucleus is essential for the successful replication o f DNA tumour viruses. To achieve this goal, viruses have adapted strategies to traverse the barriers between the plasma membrane and the nucleus o f a host cell. Two DNA tumour viruses, simian virus 40 and adenovirus, achieve the nuclear-entry step in slightly different ways. SV40 DNA enters the nucleus through the nuclear pore complexes (NPCs) in apparently intact virions. By contrast, adenovirus particles dissociate near the NPC before the viral DNA is imported into the nucleus. In both cases, karyophilic protein components o f the viruses appear to mediate nuclear entry o f the viral genomes. In this article, we discuss how an understanding o f the cell biology o f virus entry can help us understand the process o f nuclear transport.

19.
J Virol ; 70(2): 1317-22, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8551602

ABSTRACT

The nuclear localization signal of the major structural protein, Vp1, of simian virus 40 was further defined by mutagenesis. The targeting activity was examined in cells microinjected with SV-Vp1 variant viral DNAs bearing either an initiation codon mutation of the agnoprotein or mutations in the Vp1 coding sequence or microinjected with pSG5-Vp1 and pSG5-Vp1 mutant DNAs in which Vp1 or mutant Vp1 is expressed from simian virus 40 early promoter. The Vp1 nuclear localization signal functioned autonomously without agno-protein once the Vp1 protein was synthesized in the cytoplasm. The targeting activity was localized to the amino-terminal 19 residues. While replacement of cysteine 10 with glycine, alanine, or serine did not affect the activity, replacement of arginine 6 with glycine caused the cytoplasmic phenotype. When multiple mutations were introduced among residue 5, 6, 7, 16, 17, or 19, the targeting activity was found to reside in two clusters of basic residues, a cluster of lysine 5, arginine 6, and lysine 7 and a cluster of lysine 16, lysine 17, and lysine 19. The clusters are independently important for nuclear localization activity.


Subject(s)
Capsid Proteins , Capsid/metabolism , Simian virus 40/metabolism , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , Cell Nucleus/metabolism , Codon, Initiator , DNA Primers , Molecular Sequence Data , Point Mutation , Protein Sorting Signals/metabolism
20.
Proc Natl Acad Sci U S A ; 93(1): 96-100, 1996 Jan 09.
Article in English | MEDLINE | ID: mdl-8552683

ABSTRACT

All animal DNA viruses except pox virus utilize the cell nucleus as the site for virus reproduction. Yet, a critical viral infection process, nuclear targeting of the viral genome, is poorly understood. The role of capsid proteins in nuclear targeting of simian virus 40 (SV40) DNA, which is assessed by the nuclear accumulation of large tumor (T) antigen, the initial sign of the infectious process, was tested by two independent approaches: antibody interception experiments and reconstitution experiments. When antibody against viral capsid protein Vp1 or Vp3 was introduced into the cytoplasm, the nuclear accumulation of T antigen was not observed in cells either infected or cytoplasmically injected with virion. Nuclearly introduced anti-Vp3 IgG also showed the inhibitory effect. In the reconstitution experiments, SV40 DNA was allowed to interact with protein components of the virus, either empty particles or histones, and the resulting complexes were tested for the capability of protein components to target the DNA to the nucleus from cytoplasm as effectively as the targeting of DNA in the mature virion. In cells injected with empty particle-DNA, but not in minichromosome-injected cells, T antigen was observed as effectively as in SV40-injected cells. These results demonstrate that SV40 capsid proteins can facilitate transport of SV40 DNA into the nucleus and indicate that Vp3, one of the capsid proteins, accompanies SV40 DNA as it enters the nucleus during virus infection.


Subject(s)
Capsid/metabolism , DNA, Viral/metabolism , Simian virus 40/metabolism , Animals , Cell Compartmentation , Cell Nucleus/metabolism , Cells, Cultured , Fluorescent Antibody Technique, Indirect , Histones/metabolism , Macromolecular Substances , Virion/metabolism
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