Ariella Oppenheim - Academia.edu (original) (raw)

Papers by Ariella Oppenheim

Human Genetics, Oct 1, 1990

Molecular genetic studies were undertaken to determine the source of chromosomes carrying the sic... more Molecular genetic studies were undertaken to determine the source of chromosomes carrying the sickle cell allele in Israeli patients. Analysis of restriction fragment length polymorphism (RFLP) patterns (haplotypes) along the f3-globin gene cluster was performed on 31 sickle chromosomes obtained from 10 unrelated families living in Israel. One is a Caucasian Jewish family, recently found to be carrying the sickle allele, and the other 9 are Arab families of various communities. The Jewish family, previously noted not to carry African red blood cell markers, was discovered to have the most common African haplotype of the ]3-globin gene cluster, Benin. Similarly, 8 of the Arab families were also found to carry the Benin haplotype, whereas the ninth has the CAR (Central African Republic or Bantu) haplotype. The results suggest that sickle alleles in Israel originated in Africa, probably in two different regions, and migrated north into Arab and Jewish populations.

American Journal of Hematology, Nov 1, 1996

Human Genetics, Dec 1, 1990

The mechanism for elevated production of fetal hemoglobin (Hb F) in a Druze patient with beta zer... more The mechanism for elevated production of fetal hemoglobin (Hb F) in a Druze patient with beta zero-thalassemia intermedia was investigated. Heterozygous family members exhibited normal Hb F levels, suggesting that the increase in gamma-gene expression in the propositus may be partly due to anemic stress. Erythroid progenitors of these family members cultured in vitro [burst forming units (erythroid); (BFUe)] showed elevated synthesis of Hb F, indicating the existence of a genetically determined intrinsic capacity for high Hb F production in this family. The propositus was found to be homozygous for a IVS2-position 1 mutation, on the background of Mediterranean haplotype I, which is not known to be linked to high Hb F production. Moreover, extensive molecular studies of the beta-globin gene cluster, including sequence analysis of the promoter regions of the gamma-globin genes, did not reveal any cis- actin mechanism that could account for the high Hb F production in the propositus. A young niece of the propositus with beta zero-thalassemia major was recently discovered, who was homozygous for the same beta-globin allele and haplotype as the propositus. However, unlike her uncle, she does not have a high Hb F level and presents with a severe clinical course. Her inability to produce high Hb F suggests that the genetic determinant for increased gamma-gene expression in the propositus is unlinked to the beta-globin gene cluster.

Nucleus, Jul 1, 2011

molecular genetics and cell biology research for many years and has been a model for investigatio... more molecular genetics and cell biology research for many years and has been a model for investigations into mammalian gene regulation, DNA replication and transcription. Polyomaviruses are capable of infecting dividing as well as non-dividing cells. They share an unusual cell entry mechanism via binding to glycolipid molecules in caveolar/lipid raft domains at the plasma membrane. 5,6 During the first 3-6 h of infection, the polyomavirus traffics via the endosomal pathway to the ER, 7 where disassembly occurs at 5-6 h post-infection. The viruses utilize the cellular machinery for intracellular trafficking, 8 and ER chaperones for disassembly. 6,9 The 5-5.5 kb viral genome enters the nucleus complexed with nucleosomes in a chromatinlike structure termed the minichromosome. It has been suggested that the viral inner capsid proteins VP2/3 accompanies the viral genome to the nucleus by classical nucleocytoplasmic transport, via the nuclear pore. 10 Following DNA entry into the nucleus, transcription of the early region is initiated, leading to the appearance of T-antigen at 12-14 h post infection. 11 Infection is rather inefficient with only 1 in 100-200 DNA-containing

Blood Cells Molecules and Diseases, Jul 1, 2004

a-Thalassemia is among the world's most common single gene disorders, which is most prevalent in ... more a-Thalassemia is among the world's most common single gene disorders, which is most prevalent in the malaria belt. This geographic distribution has been attributed to a selective advantage of heterozygotes against this disease. Unexpectedly, we have found a high frequency of heterozygosity for deletional a-thalassemia (Àa 3.7) in Ashkenazi Jews (carrier frequency of 7.9%, allele frequency of 0.04). This population has resided in temperate climates for many centuries and was therefore not subjected to malarial selection pressure. In comparison, heterozygosity for h-thalassemia, which is highly subject to malarial selection pressure, is very low (estimated <0.1%) in this group. It is possible that founder effect and genetic drift have contributed to the high frequency of deletional a-thalassemia in Ashkenazim, as may occur in closed populations. Alternatively, we hypothesize that positive selection pressure for an as yet unknown linked allele on chromosome 16 may be a significant factor leading to this high frequency.

American Journal of Hematology, 2000

ABSTRACT α-Thalassemia is among the world&#39;s most common single gene disorders, caused... more ABSTRACT α-Thalassemia is among the world&#39;s most common single gene disorders, caused primarily by gene deletions. In Israel, where αo-trait thalassemia is uncommon, it is of particular importance because of its phenotypic interactions with β-thalassemia in hetero- and homozygotes. In a study of 232 individuals referred for molecular evaluation of anemia, 303 chromosomes carried α-globin gene abnormalities; 6 gene rearrangements and 11 point mutations were identified. This unexpected heterogeneity is in part due to the many ethnic subgroups represented by these patients. Our findings include nine unique Israeli alleles, 3 of which are described here for the first time. An equal number of point mutations was found in the α2-globin gene as compared to α1. A threonine deletion in codon 39 of the α1-globin gene, found frequently in Arabs, is unique to Israel and probably represents one of several indigenous alleles. Among Arabs, point mutations were more frequent than large deletions. Surprisingly, in Ashkenazi Jews, who resided for many centuries in a nonmalarial environment, a single α-globin gene deletion −α3.7 was found in many cases. The clinical presentation of individuals carrying two or more α-globin lesions was highly variable. In general, the severity correlated inversely with the number of functional α-globin genes. In some cases, impairment of two α-globin genes by point mutations led to a thalassemia-intermedia-like picture which could be misdiagnosed as β-thalassemia. We conclude that α-thalassemia is phenotypically and genotypically more heterogeneous than previously recognized. DNA analysis is invaluable as it provides a specific diagnosis and enables reliable genetic counseling. Am. J. Hematol. 65:196–203, 2000.© 2000 Wiley-Liss, Inc.

Journal of Virology, Apr 1, 2010

The infection process by simian virus 40 (SV40) and entry of its genome into nondividing cells ar... more The infection process by simian virus 40 (SV40) and entry of its genome into nondividing cells are only partly understood. Infection begins by binding to GM1 receptors at the cell surface, cellular entry via caveolar invaginations, and trafficking to the endoplasmic reticulum, where the virus disassembles. To gain a deeper insight into the contribution of host functions to this process, we studied cellular signaling elicited by the infecting virus. Signaling proteins were detected by Western blotting and immunofluorescence staining. The study was assisted by a preliminary proteomic screen. The contribution of signaling proteins to the infection process was evaluated using specific inhibitors. We found that CV-1 cells respond to SV40 infection by activating poly(ADP-ribose) polymerase 1 (PARP-1)-mediated apoptotic signaling, which is arrested by the Akt-1 survival pathway and stress response. A single key regulator orchestrating the three pathways is phospholipase C-gamma (PLC␥). The counteracting apoptotic and survival pathways are robustly balanced as the infected cells neither undergo apoptosis nor proliferate. Surprisingly, we have found that the apoptotic pathway, including activation of PARP-1 and caspases, is absolutely required for the infection to proceed. Thus, SV40 hijacks the host defense to promote its infection. Activities of PLC␥ and Akt-1 are also required, and their inhibition abrogates the infection. Notably, this signaling network is activated hours before T antigen is expressed. Experiments with recombinant empty capsids, devoid of DNA, indicated that the major capsid protein VP1 alone triggers this early signaling network. The emerging robust signaling network reflects a delicate evolutionary balance between attack and defense in the host-virus relationship.

Blood, 1989

Hemopoiesis is studied in vitro mainly in semisolid culture, where hemopoietic progenitors develo... more Hemopoiesis is studied in vitro mainly in semisolid culture, where hemopoietic progenitors develop into discrete colonies. We describe a liquid culture system that supports the proliferation and maturation of human erythroid progenitors. We seeded mononuclear cells from the peripheral blood (PB) of patients with beta-thalassemia in liquid medium in the presence of conditioned medium from human bladder carcinoma cells. Seven days later, RBCs, normoblasts, granulocytes, and monocytes disappeared, and the number of lymphocytes dropped considerably. In contrast, erythroid colony-forming cells increased fourfold to tenfold. The next step entailed the removal of colony- stimulating factor (CSF) and CSF-secreting cells, the exclusion of macrophages by harvesting nonadherent cells, and the lysis of T lymphocytes by treatment with monoclonal rat antihuman lymphocyte antibodies (CAMPATH-1) and complement. Reculture of the remaining cells in liquid medium supplemented with recombinant erythrop...

Blood, 1985

Analysis of methylation at the beta-globin gene cluster was carried out on DNA derived from nucle... more Analysis of methylation at the beta-globin gene cluster was carried out on DNA derived from nucleated RBCs (orthochromatic normoblasts) isolated from peripheral blood of patients with beta-thalassemia major or other congenital hemolytic anemia after splenectomy. A procedure to separate these normoblasts from the other nucleated cells of the peripheral blood was developed, providing us with a convenient source of DNA for investigating parameters related to human erythroid differentiation. Blood samples were obtained from six adult patients who express their gamma-globin genes at different levels. Inverse correlation between methylation and gene activity was consistently observed for five of the eight sites analyzed. A site 3′ to the beta gene was always unmethylated, two sites flanking the epsilon gene were always found to be methylated, and two sites 5′ to the two gamma genes, G gamma and A gamma, were hypomethylated in correlation with gamma gene activity of the individual patients...

Molecular Medicine, 1995

Background: Understanding the mechanism of developmental regulation of hemoglobin switching has s... more Background: Understanding the mechanism of developmental regulation of hemoglobin switching has scientific as well as clinical relevance because of the influence of fetal hemoglobin (HbF) production in adulthood on the clinical manifestation of thalassemia and sickle cell anemia. We have previously found that the normal developmental patterns of globin gene expression are recapitulated in an experimental system of primary cultures that support differentiation of erythroid progenitors. We further found that high activities of the transcriptional activators, GATA-1 and SPI, are associated with normal adult erythroid differentiation. Materials and Methods: In the present work, we have studied the activities of GATA-1 and SPI during differentiation of cultured erythroid progenitors derived from cord blood and from fetal livers, as well as from ,3Othalassemia patients. Results: The results showed high GATA-1 binding activity and very low SPI activity in the fetal liver cultures. This pattern was in contrast to cultures derived from normal adult peripheral blood, in which both GATA-1 and SPI activities were high. Cord blood cultures showed an additive combination of "adult" and "fetal" patterns. The progenitors derived from a 13-thalassemia patient with high HbF production showed "fetal" pattern. On the other hand, in cultures of 2 13-thalassemia patients without high HbF, "adult" pattern was observed. Conclusions: In the present work, we show that human fetal and adult erythroid progenitors are distinct in their transcription factors, and that the commitment to fetal or adult program occurs at a very early differentiation stage. Our studies also demonstrate that under anemic stress, recruitment of fetal progenitors may occur in adulthood.

American journal of human genetics, 1990

A common glucose-6-phosphate dehydrogenase (G6PD) variant characterized by severe enzyme deficien... more A common glucose-6-phosphate dehydrogenase (G6PD) variant characterized by severe enzyme deficiency and B-like electrophoretic mobility is called "G6PD-Mediterranean" because it is found in different populations around the Mediterranean Sea. Sequence analysis of Italian subjects has revealed that the molecular basis of G6PD-Mediterranean is a single C-T transition at nucleotide position 563, causing a serine phenylalanine replacement at amino acid position 188. Most G6PD-Mediterranean subjects also have a silent C-T transition (without amino acid replacement) at nucleotide position 1311. Twenty-one unrelated individuals from Saudi Arabia, Iraq, Iran, Jordan, Lebanon, and Israel with both severe G6PD deficiency and B-like electrophoretic mobility were tested for both mutations by using amplification followed by digestion with appropriate restriction enzymes. All but one had the 563 mutation, and, of these, all but one had the 1311 mutation. Another 24 unrelated Middle Easte...

Respiratory Research, 2007

Background: Sepsis remains the leading cause of death in critically ill patients. One of the prim... more Background: Sepsis remains the leading cause of death in critically ill patients. One of the primary organs affected by sepsis is the lung, presenting as the Acute Respiratory Distress Syndrome (ARDS). Organ damage in sepsis involves an alteration in gene expression, making gene transfer a potential therapeutic modality. This work examines the feasibility of applying simian virus 40 (SV40) vectors for pulmonary gene therapy. Methods: Sepsis-induced ARDS was established by cecal ligation double puncture (2CLP). SV40 vectors carrying the luciferase reporter gene (SV/luc) were administered intratracheally immediately after sepsis induction. Sham operated (SO) as well as 2CLP rats given intratracheal PBS or adenovirus expressing luciferase served as controls. Luc transduction was evaluated by in vivo light detection, immunoassay and luciferase mRNA detection by RT-PCR in tissue harvested from septic rats. Vector abundance and distribution into alveolar cells was evaluated using immunostaining for the SV40 VP1 capsid protein as well as by double staining for VP1 and for the surfactant protein C (proSP-C). Immunostaining for T-lymphocytes was used to evaluate the cellular immune response induced by the vector. Results: Luc expression measured by in vivo light detection correlated with immunoassay from lung tissue harvested from the same rats. Moreover, our results showed vector presence in type II alveolar cells. The vector did not induce significant cellular immune response. Conclusion: In the present study we have demonstrated efficient uptake and expression of an SV40 vector in the lungs of animals with sepsis-induced ARDS. These vectors appear to be capable of in vivo transduction of alveolar type II cells and may thus become a future therapeutic tool.

Proceedings of the National Academy of Sciences, 1986

Introduction of DNA into human hemopoietic cells is required for the study of regulatory mechanis... more Introduction of DNA into human hemopoietic cells is required for the study of regulatory mechanisms operating in these cells, as well as for possible procedures of gene therapy. However, with hemopoietic cells the conventional technique of calcium phosphate precipitation is inefficient. The pathway of encapsidation of plasmid DNA as simian virus 40 (SV40) pseudovirions for the introduction of new genetic material was therefore investigated. Encapsidation was achieved in COS (monkey kidney) cells, which express SV40 large tumor (T) antigen constitutively. The vector, pSO, was introduced to the COS cells by DNA transfection. It carried the SV40 origin of replication (ori), to facilitate replication of the plasmid in the COS cells. The SV40 capsid proteins were supplied in trans by a helper SV40 virus. The bacterial chloramphenicol acetyltransferase gene cat was used as a model for gene transmission. After encapsidation, the pseudovirions were used in infection of the human erythroleuk...

Nucleic Acids Research, 1993

GATA-1 Is a central transcription-activator of erythroid differentiation. In the present work we ... more GATA-1 Is a central transcription-activator of erythroid differentiation. In the present work we have studied the kinetics of Its expression and activity during development of normal human erythroid progenitors, grown in primary cultures. In response to the addition of erythropoietin (Epo), the cells undergo proliferation and differentiation in a synchronized fashion. This recently developed experimental system allows biochemical dissection of erythroid differentiation in a physiological meaningful environment. No DNA-blnding activity of GATA-1 could be detected before the addition of Epo, although a very low level of mRNA was observed. Following Epo addition there was a sharp parallel rise in both mRNA and DNA-blnding activity, consistent with positive autoregulation of the GATA-1 gene. After reaching a peak on day 7-9, both mRNA and protein activity decreased. The binding activity of the ubiquitous factor SP1 showed a biphasic pattern; Its second peak usually coincided with the GATA-1 peak, suggesting that SP1 also plays a specific role in erythroid maturation. The highest activity of GATA-1 per erythroid cell was found on day 6-8, immediately preceding the major rise In globin gene mRNA and in the number of hemoglobinlzed cells. The results Imply that a high level of GATA-1 activity Is necessary for globin gene expression and erythroid maturation, suggesting that a requirement for a threshold concentration of GATA-1 Is part of the mechanism that determines the final steps of erythroid maturation.