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J M Petersen

Publications and source records attributed to J M Petersen.

At least 19 recordsLinked to original sources
PubMed2001

Multiple vesiculoviral matrix proteins inhibit both nuclear export and import.

The matrix (M) protein of vesicular stomatitis virus inhibits both nuclear import and export. Here, we demonstrate that this inhibitory property is conserved between the M proteins from two other vesiculoviruses, chandipura virus and spring viremia carp virus. All three M proteins completely block nuclear transport of spliced mRNA, small nuclear RNAs, and small nuclear ribonucleoproteins and slow the nuclear transport of many other cargoes. In all cases where transport was merely slowed by the M proteins, the chandipura virus M protein had the strongest inhibitory activity. When expressed in transfected HeLa cells, active M proteins displayed prominent association with the nuclear rim. Moreover, mutation of a conserved methionine abolished both the inhibitory activity and efficient targeting of the M proteins to the nuclear rim. We propose that all of the vesiculoviral M proteins associate with the same nuclear target, which is likely to be a component of the nuclear pore complex.

Active Transport, Cell Nucleus↗
PubMed2000

The matrix protein of vesicular stomatitis virus inhibits nucleocytoplasmic transport when it is in the nucleus and associated with nuclear pore complexes.

The matrix (M) protein of vesicular stomatitis virus (VSV) is a potent inhibitor of bidirectional nuclear transport. Here we demonstrate that inhibition occurs when M protein is in the nucleus of Xenopus laevis oocytes and that M activity is readily reversed by a monoclonal antibody (alphaM). We identify a region of M protein, amino acids 51 to 59, that is required both for inhibition of transport and for efficient recognition by alphaM. When expressed in transfected HeLa cells, M protein colocalizes with nuclear pore complexes (NPCs) at the nuclear rim. Moreover, mutation of a single amino acid, methionine 51, eliminates both transport inhibition and targeting to NPCs. We propose that M protein inhibits bidirectional transport by interacting with a component of the NPC or an NPC-associated factor that participates in nucleocytoplasmic transport.

Active Transport, Cell Nucleus↗
PubMed1996

Solution structure of the ETS domain from murine Ets-1: a winged helix-turn-helix DNA binding motif.

Ets-1 is the prototypic member of the ets family of transcription factors. This family is characterized by the conserved ETS domain that mediates specific DNA binding. Using NMR methods, we have determined the structure of a fragment of murine Ets-1 composed of the 85 residue ETS domain and a 25 amino acid extension that ends at its native C-terminus. The ETS domain folds into a helix-turn-helix motif on a four-stranded anti-parallel beta-sheet scaffold. This structure places Ets-1 in the winged helix-turn-helix (wHTH) family of DNA binding proteins and provides a model for interpreting the sequence conservation of the ETS domain and the specific interaction of Ets-1 with DNA. The C-terminal sequence of Ets-1, which is mutated in the v-Ets oncoprotein, forms an alpha-helix that packs anti-parallel to the N-terminal helix of the ETS domain. In this position, the C-terminal helix is poised to interact directly with an N-terminal inhibitory region in Ets-1 as well as the wHTH motif. This explains structurally the concerted role of residues flanking the ETS domain in the intramolecular inhibition of Ets-1 DNA binding.

Amino Acid Sequence↗
PubMed1996

Structural coupling of the inhibitory regions flanking the ETS domain of murine Ets-1.

Several members of the ets gene family of transcription factors show negative regulation of DNA binding by intramolecular interactions. A structural mechanism for this auto-inhibition is investigated using a 161-residue N-terminal deletion mutant of murine Ets-1, Ets-1 delta N280. This protein shows a similar reduced affinity for DNA as native Ets-1 because it contains the ETS domain in context of the flanking amino- and carboxy-terminal regions that together mediate repression of DNA binding. The secondary structure of Ets-1 delta N280 was determined using NMR chemical shift, NOE, J coupling, and amide hydrogen exchange information. In addition to the winged helix-turn-helix ETS domain, Ets-1 delta N280 contains two alpha-helices in the amino-terminal inhibitory region and one alpha-helix in the carboxy-terminal inhibitory region. Chemical shift comparisons were made between this protein and an activated form of Ets-1 lacking the amino-terminal inhibitory region. The spectral differences demonstrate that the amino- and carboxy-terminal inhibitory sequences are structurally coupled to one another, thus explaining the observation that both regions are required for the repression of DNA binding. Furthermore, these data show that the inhibitory sequences also interact directly with the first helix of the intervening ETS domain, thereby providing a pathway for the repression of DNA binding. These results lead to a model of an inhibitory module in Ets-1 composed of both the amino- and carboxy-terminal regions interfaced with the ETS domain. This establishes the structural framework for understanding the intramolecular inhibition of Ets-1 DNA binding.

Amino Acid Sequence↗
PubMed1996

Characterization of the cooperative function of inhibitory sequences in Ets-1.

DNA binding by the eukaryotic transcription factor Ets-1 is negatively regulated by an intramolecular mechanism. Quantitative binding assays compared the DNA-binding activities of native Ets-1, three deletion mutants, and three tryptic fragments. Ets-1 and activated Ets-1 polypeptides differed in DNA-binding affinity as much as 23-fold. Inhibition was mediated by two regions flanking the minimal DNA-binding domain. Both regions regulated affinity by enhancing dissociation of the protein-DNA complex. Three lines of evidence indicated that inhibition requires cooperative interaction between the two regions: first, the two inhibitory regions acted through a common mechanism; second, neither region functioned independently of the other; finally, mutation of the C-terminal inhibitory region altered the conformation of the N-terminal inhibitory region. In addition, partial proteolysis detected an identical altered conformation in the N-terminal inhibitory region of Ets-1 bound to DNA. This finding suggested that repression is transiently disrupted during DNA binding. These results provide evidence that the two inhibitory regions of Ets-1 are structurally, as well as functionally, coupled. In addition, conformational change is shown to be a critical component of the inhibition mechanism. A cooperative, allosteric model of autoinhibition is described. Autoinhibition of Ets-1 could be relieved by either protein partner(s) or posttranslational modifications.

Allosteric Regulation↗
PubMed1995

Modulation of transcription factor Ets-1 DNA binding: DNA-induced unfolding of an alpha helix.

Conformational changes, including local protein folding, play important roles in protein-DNA interactions. Here, studies of the transcription factor Ets-1 provided evidence that local protein unfolding also can accompany DNA binding. Circular dichroism and partial proteolysis showed that the secondary structure of the Ets-1 DNA-binding domain is unchanged in the presence of DNA. In contrast, DNA allosterically induced the unfolding of an alpha helix that lies within a flanking region involved in the negative regulation of DNA binding. These findings suggest a structural basis for the intramolecular inhibition of DNA binding and a mechanism for the cooperative partnerships that are common features of many eukaryotic transcription factors.

Base Sequence↗
PubMed1995

DMA and DMB are the only genes in the class II region of the human MHC needed for class II-associated antigen processing.

Previous studies have shown that homozygous mutations between the LMP2 and DNA loci in the human MHC cause class II molecules to be abnormally conformed and unstable in the presence of SDS at low temperature, and impede class II-associated Ag processing and presentation. These abnormalities result from impaired ability to form intracellular class II/peptide complexes that predominate in normal cells. We show in this work that this defect results from deficient expression of either the DMA or the DMB gene. Human B-LCL.174 (DR3) cells, which have a deletion of all known expressible genes in the class II region, express transgene-encoded HLA-DR3, but have the abnormalities. Transfer of cosmid HA14, which contains the DMA and DMB genes, into .174 (DR3) cells restored normal DR3 conformation, stability in 0.4% SDS at 0 degree, and ability to process and present tetanus toxoid, but only when both DMA and DMB mRNAs were present. The requirement for both genetic expressions in engendering normal phenotypes was confirmed by transferring the cloned genes into .174 (DR3) cells separately or together. Because normal phenotypes were fully restored in transferent cells expressing DMA plus DMB, other genes in the approximately 1-mb homozygous class II region deletion in .174 (DR3) cells either do not participate in or are dispensable for apparently normal production of intracellular class II/peptide complexes. The properties of DM-deficient EBV-transformed B lymphoblastoid cell lines (LCLs) suggest ways of identifying humans in whom DM deficiency contributes to congenital immunodeficiency and malignancy.

Antigen Presentation↗
PubMed1995

Gunshot cholecystitis.

A 15-year-old boy developed traumatic cholecystitis from a BB shot that lodged in his gallbladder. This is an unusual cause of gallbladder disease, and we review the literature.

Adolescent↗
PubMed1994

Secondary structure of the ETS domain places murine Ets-1 in the superfamily of winged helix-turn-helix DNA-binding proteins.

The members of the ets gene family of transcription factors are characterized by a conserved 85-residue DNA-binding region, termed the ETS domain, that lacks sequence homology to structurally characterized DNA-binding motifs. The secondary structure of the ETS domain of murine Ets-1 was determined on the basis of NMR chemical shifts, NOE and J-coupling constraints, amide hydrogen exchange, circular dichroism, and FT-IR spectroscopy. The ETS domain is composed of three alpha-helices (H) and four beta-strands (S) arranged in the order H1-S1-S2-H2-H3-S3-S4. The four-stranded antiparallel beta-sheet is the scaffold for a putative helix-turn-helix DNA recognition motif formed by helices 2 and 3. The 25 residues extending beyond the ETS domain to the native C-terminus of the truncated Ets-1 also contain a helical segment. On the basis of the similarity of this topology with that of catabolite activator protein (CAP), heat shock factor (HSF), and hepatocyte nuclear factor (HNF-3 gamma), we propose that ets proteins are members of the superfamily of winged helix-turn-helix DNA-binding proteins.

Amino Acid Sequence↗
PubMed1992

Correction of antigen-specific T-lymphocyte function by recombinant cytokines in children infected with human immunodeficiency virus type 1.

To determine the role of cytokines in the immunodeficiency of children infected with human immunodeficiency virus type 1 (HIV-1), we compared the antigen-specific (tetanus toxoid-induced) T-lymphocyte blastogenesis of HIV-1-infected patients with and without the addition of exogenous interleukin-1 and interleukin-2. Acquisition of in vitro antigen-specific immunologic function was seen in some patients after the addition of exogenous cytokines. The antigen-specific immunodeficiency in some HIV-1-infected children is due to defects in cytokine production rather than to an absence of antigen-specific T lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Interaction of murine ets-1 with GGA-binding sites establishes the ETS domain as a new DNA-binding motif.

The proto-oncogene ets-1 is the founding member of a new family of eukaryotic transcriptional regulators. Using deletion mutants of murine ets-1 cDNA expressed in Escherichia coli, we show that the DNA-binding domain corresponds closely to the ETS domain, an 85-amino-acid region that is conserved among ets family members. To investigate the specificity of DNA binding of the ETS domain, we mapped the DNA contacts of a monomeric Ets-1 fragment by chemical protection and interference assays. DNA backbone interactions span a 20-nucleotide region and are localized on one face of the helix. Close phosphate and base contacts are restricted to 10 central nucleotides. Contacts map to the major groove in the center of the site. Flanking minor groove interactions also are predicted. To determine the sequence preference in the close contact zone, we selected a pool of high-affinity binding sites using a purified Ets-1 carboxy-terminal fragment. Our Ets-1-selected consensus, 5'-A/GCCGGAA/TGT/C-3', differs from the binding consensus for the Drosophila ETS domain protein E74A, suggesting that specificity of action of ets family members is mediated by the ETS domain. Compared to other well-characterized classes of DNA-binding proteins, Ets-1 produces a unique pattern of DNA contacts. These studies demonstrate that the ETS domain proteins bind DNA in a novel manner.

Animals↗
PubMed1989

Sucralfate delays gastric emptying of liquids and solids in duodenal ulcer patients.

Gastric emptying studies were performed on nine healthy volunteers and ten duodenal ulcer (DU) patients utilizing a dual radionuclide technique to assess simultaneously emptying rates of liquid (111In labeled water) and solid (99mTc sulfur colloid labeled chicken liver) components of a meal. One gram of sucralfate was compared to placebo in separate days in a randomized double-blind crossover fashion. Subjects ingested the radiolabeled test meal 1 h after receiving medication, and gastric emptying was monitored for 3 h using a gamma camera interfaced with a computer. We found that DU patients had significantly faster gastric emptying of solids (P less than 0.05) compared to normals on the placebo days, while liquid emptying rates were similar. Sucralfate, in the DU patients, significantly (P less than 0.05) slowed gastric emptying of water from 20 to 40 min and emptying of the solid component from 100-160 min after the meal compared to placebo. In normal subjects, gastric emptying of liquids and solids was not significantly affected by sucralfate. We conclude that slowing of gastric emptying, possibly mediated through aluminum ions, occurs in DU patients on sucralfate. This may be one mechanism by which sucralfate enhances healing and decreases recurrence of duodenal ulcer.

Adult↗
PubMed1987

Improved survival with primary sclerosing cholangitis. A review of clinicopathologic features and comparison of symptomatic and asymptomatic patients.

The clinicopathologic features and natural history of primary sclerosing cholangitis were reviewed in 53 patients followed at the Yale Liver Center during the past 30 yr. At presentation, the mean age of patients was 46 yr, and the male to female ratio was 1.4:1. Biliary sclerosis was limited to the intrahepatic ductal system in 21% of the patients. Fifty-three percent of the patients had mild disease without portal hypertension at presentation, and 25% had no symptoms attributable to their liver disease. Long-term follow-up was available for 42 patients and averaged 56 mo. Over this period, 16 patients remained mildly symptomatic, and 11 were asymptomatic. Survival was calculated by a Kaplan-Meier life-table analysis and demonstrated that 75% of the patients were alive 9 yr after the diagnosis of primary sclerosing cholangitis. A multivariate analysis of clinical features revealed that hepatomegaly and a serum bilirubin level greater than 1.5 mg/dl at the onset of disease were independent discriminators of a poor prognosis. Patients referred to this university medical center displayed different clinical characteristics than previously reported in primary sclerosing cholangitis. A higher percentage were older, female, and asymptomatic, and more had disease limited to the intrahepatic ductal system. Survival was also considerably improved in this group of patients and suggests that the long-term prognosis for patients with primary sclerosing cholangitis may be considerably better than previously believed.

Adolescent↗
PubMed1985

Small noncleaved B cell Burkitt-like lymphoma with chromosome t(8;14) translocation and Epstein-Barr virus nuclear-associated antigen in a homosexual man with acquired immune deficiency syndrome.

This case report describes new manifestations of the acquired immune deficiency syndrome (AIDS) in a promiscuous homosexual man. Investigation of upper gastrointestinal bleeding in the patient lead to discovery of a high-grade, small, noncleaved cell (Burkitt-like) gastroduodenal lymphoma with visceral and extralymphatic extension. Specific phenotyping of the lymphoma revealed that it was a monoclonal B cell lymphoma of mu kappa isotype. An in vitro cell line was established that was Epstein-Barr virus nuclear-associated antigen-positive. The lymphoma cells displayed a t(8;14) translocation similar to endemic African Burkitt lymphoma. Epstein-Barr virus genomes were identified in the lymphoma and an axillary lymph node biopsy specimen by molecular hybridization. These data strongly suggest that Epstein-Barr virus actively infected this patient. However, he showed normal Epstein-Barr virus-specific serologic responses, indicating an immune defect against the virus.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Gastrointestinal neurofibromatosis.

Progressive anemia, melena, and sudden massive upper gastrointestinal bleeding in a man with cutaneous neurofibromatosis (von Recklinghausen's disease) since childhood prompted endoscopic demonstration of multiple gastric neurofibromas. One source of gastric bleeding removed by endoscopic electrosurgery proved to be a malignant schwannoma (spindle cell sarcoma). A pulmonary schwannoma, multifocal intracerebral spindle cell sarcomas, an extra-adrenal pheochromocytoma, and ocular neurofibromas were other features of this neuroectodermal dysplasia. Neurogenic tumors of the gastrointestinal tract are rare, commonly present with dyspepsia, abdominal pain, anemia, or hemorrhage, and should be suspect in the clinical setting of cutaneous neurofibromatosis. In the patient with systemic neurofibromatosis, endoscopic removal represents a safe method of diagnosis and treatment of bleeding neoplasms in the stomach or duodenum.

Adrenal Gland Neoplasms↗