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J Rappaport

Publications and source records attributed to J Rappaport.

At least 73 records · Page 4Linked to original sources
PubMed1991

Interactions between adenovirus E1A and members of the AP-1 family of cellular transcription factors.

We have studied interactions between bacterially produced E1A linked to Sepharose and the various DNA-binding proteins present in HeLa cell nuclear extracts (NE). DNA-binding activities and cross-reactive polypeptides recognizing the cAMP-responsive element (CRE) and the activator protein 1 (AP1) sites were bound to the E1A column, whereas nuclear factor 1 (NF1) and the activator protein 2 (AP2) DNA-binding activities were not retained by E1A. The binding activities that were retained belonged to the CRE and JUN protein family, as judged by Western blot analysis. Authentic CRE-BP1, c-Jun and c-Fos proteins produced by in-vitro translation also bound to the E1A column. However, efficient binding of in-vitro-translated CRE-BP1 and c-Fos proteins to E1A required preincubation with NE. We show here that immobilized E1A sequesters several cellular upstream transcription activators, and suggest a role for members of the AP1 family of transcription factors in E1A-mediated gene regulation.

Adenovirus Early Proteins↗
PubMed1991

Tat-regulated production of multimerized TAR RNA inhibits HIV-1 gene expression.

Transcriptional activation of gene expression directed by the long terminal repeat (LTR) of the human immunodeficiency virus type 1 (HIV-1) requires both the Tat activation response element (TAR) and the Tat protein. Mutants lacking a functional tat gene are not able to replicate. An approach we have used to suppress HIV-1 gene expression is based on the controlled overexpression of multimerized TAR sequences, which results in the sequestration of one or more components of the Tat response. Since Tat has no known cellular analog, a modified HIV-1 LTR, which is highly induced by the presence of Tat, was used to promote the expression of the multimerized TAR (poly-TAR) specifically in the presence of Tat. Cotransfection of an HIV-1 LTR-controlled poly-TAR plasmid with LTR-Tat and LTR-CAT plasmids inhibited the level of the reporter gene activity (CAT) as much as 97%. The downregulation of HIV-1 gene expression observed was dependent on the quantity of transfected poly-TAR as well as the number of tandem TAR repeats expressed per unit transcript. Similar constructs lacking either LTR upstream sequences or the TAR sequence had no significant effect, suggesting that the competitive effect was mediated at the RNA level and that it was the nascent RNA, rather than DNA, that was recognized by the Tat protein. Tat-regulated production of the poly-TAR transcript provides a means for dissecting the mechanism of Tat-mediated trans-activation of the HIV-1 LTR. The ability to regulate a viral inhibitory gene so that it is expressed only when needed should prove useful in devising an antiviral strategy through gene therapy.

Base Sequence↗
PubMed1990

A nuclear protein derived from brain cells stimulates transcription of the human neurotropic virus promoter, JCVE, in vitro.

The 98-base pair enhancer/promoter sequence is critical for cell type-specific transcription of the human neurotropic viral promoter, JCVE, in glial cells. Transcriptionally active extracts were prepared from glial cells and used to identify cis- and trans-acting regulatory elements that are involved in the glial-specific activation of the JCVE promoter. Results indicate that multiple regulatory sequences within the 98-base pair repeat specifically bind to nuclear proteins present in glial cells and positively regulate viral early RNA synthesis. The central region of the repeat, designated domain-B, interacts with a 45-kDa nuclear protein present in brain cells. This brain-specific protein was purified by conventional and DNA affinity chromatography. Complementation of the highly purified protein with HeLa extract significantly increased JCVE promoter activity. Thus, association of the novel glial-origin transcription factor with its target sequence increases transcription of the JCVE promoter in a non-glial context.

Animals↗
PubMed1990

Temperament, behavior problems, and learning skills in very low birth weight preschoolers.

The relationship between temperament, behavior problems, and learning skill abilities in preschool children who were born with very low birth weight (VLBW) is described. Subjects were 37 4-year-olds who weighed less than 1,500 grams at birth, were appropriate for gestational age, and free from congenital anomalies (M birth weight = 1,201 grams). Data were gathered when the children were 48 months chronological age and analyzed using point biserial and Pearson product moment correlation, chi square, and MANOVA. Temperament characteristics of rhythmicity, intensity, and persistence were related to behavior problems and learning skill abilities. Mothers reported more children with behavior problems than expected in the general population. Children with four or more behavior problems had significantly lower skill achievement scores than children with fewer behavior problems.

Child Behavior Disorders↗
PubMed1990

Trans-activation of the JC virus late promoter by the tat protein of type 1 human immunodeficiency virus in glial cells.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC virus (JCV), a human papovavirus. PML is a relatively rare disease seen predominantly in immunocompromised individuals and is a frequent complication observed in AIDS patients. The significantly higher incidence of PML in AIDS patients than in other immunosuppressive disorders has suggested that the presence of human immunodeficiency virus type 1 (HIV-1) in the brain may directly or indirectly contribute to the pathogenesis of this disease. In the present study we have examined the expression of the JCV genome in both glial and non-glial cells in the presence of HIV-1 regulatory proteins. We find that the HIV-1-encoded trans-regulatory protein tat increases the basal activity of the JCV late promoter, JCVL, in glial cells. In a reciprocal experiment, the JCV early protein, the large tumor antigen, stimulates expression from JCVL and HIV-1 long terminal repeat promoter in both glial and non-glial cells. This trans-activation occurs at the level of RNA synthesis, as measured by the rate of transcription, stability of the message, and translation. We conclude that the presence of the HIV-1-encoded tat protein may positively affect the JCV lytic cycle in glial cells by stimulating JCV gene expression. Our results suggest a mechanism for the relatively high incidence of PML in AIDS patients than in other immunosuppressive disorders. Furthermore, our findings indicate that the HIV-1 regulatory protein tat may stimulate other viral and perhaps cellular promoters, in addition to its own.

Cell Line↗
PubMed1990

Regulation of the human neurotropic virus promoter by JCV-T antigen and HIV-1 tat protein.

We compared the ability of HIV-1 tat protein and JCV T-antigen in inducing transcription from the JCV late promoter, JCVL. A JCVL promoter-chloramphenicol acetyltransferase plasmid (pJCL-CAT) was transfected into human glial cells alone or together with plasmids producing T-antigen and tat protein. CAT enzyme activity obtained from the transfected cells indicated that both JCV T-antigen and HIV-1 tat proteins stimulated JCV late gene expression. However, the level of induction mediated by tat protein was significantly higher than that obtained with T-antigen. Moreover, in contrast to JCV T-antigen, tat stimulated JCVL-promoter activity over a narrow range of ptat expressor plasmid concentration. Co-transfection of both T-antigen and tat plasmids at optimal concentrations resulted in greater than additive CAT activity from the JCVL promoter. This synergism suggests that the two activator proteins utilize alternative mechanisms to exert their effects. Using deletion mutations from the 5' end of the JCVL promoter, we demonstrated that different regions within the JCV enhancer/promoter are important for T-antigen and tat induction, implying that these activators function through distinct targets to increase JCVL promoter activity.

Antigens, Polyomavirus Transforming↗
PubMed1989

Human herpes virus-6 increases HIV-1 expression in co-infected T cells via nuclear factors binding to the HIV-1 enhancer.

Human Herpes virus-6 (HHV-6) can co-infect with HIV-1 human CD4+ T-cells, leading to accelerated cell death, and factors in HHV-6-infected cells stimulate HIV-1 LTR directed gene expression. In this study, we have examined the mechanism of HIV-1 activation by HHV-6 and localized the cis-acting sequences of HIV-1 LTR responsive to trans-activation. Increased HIV-1 LTR directed gene expression is obtained in HIV-1 infected cells co-infected with HHV-6, or in HHV-6 infected cells co-transfected with the HIV-1 tat gene. Parallel increases of HIV-1-specific transcripts are seen by in situ hybridization in HHV-6/HIV-1 doubly infected cells as compared to single HIV-1 infection. Similarly, infection by HHV-6 increases the steady-state level of HIV-1 LTR mRNA that parallels CAT enzymatic activity, suggesting a transcriptional and/or post-transcriptional activation. Sequences necessary for HIV-1 LTR activation by HHV-6 are distinct from those required for that tat response and map to a region of the HIV-1 LTR from -103 to -48. The HIV-1 enhancer sequence (-105 to -80) is sufficient to confer HHV-6 inducibility to a heterologous promoter, and nuclear protein(s) activated or induced by HHV-6 infection specifically bind to the NF kappa B motifs of the HIV-1 enhancer region.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1989

Economic predictors of mental health service utilization: a time-series analysis.

This research was designed to understand the relationships between economic indicators and mental health service utilization. Six monthly and three quarterly time-series analyses were done to assess the time-dependent association between three state-level economic indices and two measures of mental health service utilization. Consistent with the existing literature, increases in manufacturing employment were inversely related to both first admissions in state hospitals and case openings in community outpatient facilities. Labor force participation was also inversely related to first admissions to state hospitals. No relationship was found between service employment and either of the mental health service use indices. The specific findings suggest that two processes may be operating in the relationship of labor force participation and manufacturing employment with mental health service utilization. Some of the findings suggest a "crisis" process, in which service use increases rapidly following an economic stressor, whereas other findings suggest a more insidious process, in which economic stressors slowly weaken the mental health of the community and eventually lead to increased mental health service use. These results can be used to better inform social policy and preventive interventions by highlighting the human costs of changes in economic well-being. The need for more ecological research is discussed.

Adaptation, Psychological↗
PubMed1989

Cell type-specific expression of JC virus early promoter is determined by positive and negative regulation.

We analyzed control sequences of the human papovavirus JC virus (JCV) to define the cis-acting elements that regulate specific expression of the viral early region genes in glial cells. Nuclear run-on transcription, S1 analysis, and chloramphenicol acetyltransferase enzyme activity in a transient transfection assay established that the cell type-specific expression of JCV early genes is determined at the transcriptional level. Using DNase footprinting analysis of nuclear proteins prepared from glial and nonglial cells, we located four regions within the JCV control sequences that specifically interacted with the proteins. In glial cells, all four domains contributed to the specific expression of a heterologous promoter, whereas in nonglial cells, two protein-binding regions showed no effect on basal transcriptional activity and the other two domains significantly downregulated transcription of the promoter. We conclude that cell type-specific transcription of the JCV early promoter is under both positive and negative regulation in eucaryotic cells.

Base Sequence↗
PubMed1989

Patient satisfaction within an emergency department: the impact of a hospital volunteer program.

During the past decade, the proliferation of managed care plans and the reduction of governmental reimbursement has seriously eroded hospital revenues. As a result, hospitals are managing with less resources yet confronting more complex patient problems, particularly in the Emergency Department of the hospital. Since the Emergency Department is frequently the major interface between the hospital and the community, it is essential that patients have a positive experience while obtaining care. This study explores the impact of a hospital-based volunteer program upon patient satisfaction within an Emergency Department and the implications for hospital administrators.

Consumer Behavior↗
PubMed1989

The acidic amino-terminal region of the HIV-1 Tat protein constitutes an essential activating domain.

The Tat protein encoded by the human immunodeficiency virus (HIV) is an efficient activator of HIV gene expression. Many eukaryotic transcriptional activators contain a nucleic acid binding domain and a separate activating domain. These activating regions are acidic and often amphipathic. The amino terminus of the HIV-1 Tat protein is acidic with a periodicity of acidic, polar, and hydrophobic residues consistent with that of an amphipathic alpha helix. This region appears to be important for Tat function. We have analyzed the functional significance of acidic residues within the amino-terminal region of Tat by means of site-directed mutagenesis and by testing the capacity of mutant proteins to trans-activate the viral long terminal repeat (LTR) Conservative changes (acidic to acidic) were well tolerated, whereas acidic to neutral and acidic to basic changes markedly reduced Tat activity. The relative importance of each of the three acidic residues correlated with proximity to the amino terminus. Substitution of the entire domain with heterologous sequences that might form an acidic, amphipathic alpha helix partially restored activity when compared with an amino-terminal truncation mutant. In contrast to the observed importance of acidic residues, hydroxylated residues between amino acids 40 and 47 were dispensable for Tat function. These data suggest that the acidity of the amino terminal region is important for Tat function and that Tat-mediated trans-activation may be similar to that of other known activator proteins.

Amino Acid Sequence↗
PubMed1988

Nuclear factors in human brain cells bind specifically to the JCV regulatory region.

The human polyomavirus, JCV, differs from other papovaviruses in its tissue tropism for human glial cells. Transcription of the early region of the virus, at least in part, contributes to the tissue specificity of JCV. In this study, we have synthesized oligonucleotides which span the JCV 98 bp repeat unit. Using gel mobility shift and UV cross-linking assays, we have demonstrated that four proteins from a human fetal brain extract interact specifically with the JCV promoter/enhancer. Two proteins of 82 kd and 78/80 kd recognize the 5'- and 3'-terminal regions of the JCV 98 bp repeat sequence, respectively. The mol. wt of these proteins are similar in HeLa and brain extracts. In contrast, the proteins which recognize the central region of the 98 bp enhancer are distinct in HeLa (85 kd) and fetal brain (45 kd) extracts. The possible role of these proteins in tissue-specific expression of the JCV early promoter in brain cells is discussed.

Base Sequence↗
PubMed1988

Citizen participation, perceived control, and psychological empowerment.

The research integrates the citizen participation literature with research on perceived control in an effort to further our understanding of psychological empowerment. Eleven indices of empowerment representing personality, cognitive, and motivational measures were identified to represent the construct. Three studies examined the relationship between empowerment and participation. The first study examined differences among groups identified by a laboratory manipulation as willing to participate in personally relevant or community relevant situations. Study II examined differences for groups defined by actual involvement in community activities and organizations. Study III replicated Study II with a different population. In each study, individuals reporting a greater amount of participation scored higher on indices of empowerment. Psychological empowerment could be described as the connection between a sense of personal competence, a desire for, and a willingness to take action in the public domain. Discriminant function analyses resulted in one significant dimension, identified as pyschological empowerment, that was positively correlated with leadership and negatively correlated with alienation.

Adolescent↗
PubMed1988

Missense mutations in an infectious human immunodeficiency viral genome: functional mapping of tat and identification of the rev splice acceptor.

Single nucleotide alterations were introduced into an infectious clone of human immunodeficiency virus type 1 to create a series of missense mutants in the tat coding region. Although mutations in a proline-rich region and a basic lysine-arginine-rich region resulted in wild-type phenotypes, five of six mutations in a cysteine-rich domain completely abolished tat activity and virus replication. One cysteine mutant retained tat activity but was negative for virus expression. Surprisingly, this mutant could not be complemented by tat, and virus expression was restored only by cotransfection with a plasmid expressing the rev gene. Another mutant with an alteration toward the C-terminal region showed significantly reduced tat activity and required complementation by a combination of tat and rev for virus replication. Further analysis revealed that a previously unrecognized splice acceptor site within this region, apparently used to generate the rev mRNA, had been altered. We provide evidence suggesting that tat and rev proteins are encoded by distinct mRNA species.

Amino Acid Sequence↗
PubMed1988

Transcription elongation factor SII interacts with a domain of the large subunit of human RNA polymerase II.

Genomic sequences for the large subunit of human RNA polymerase II corresponding to a part of the fifth exon were inserted into an expression vector at the carboxy-terminal end of the beta-galactosidase gene. The in-frame construct produced a 125-kilodalton fusion protein, containing approximately 10 kilodaltons of the large subunit of RNA polymerase II and 116 kilodaltons of beta-galactosidase. The purified bacterially produced fusion protein inhibited specific transcription from the adenovirus type 2 major late promoter, while beta-galactosidase had no effect. This effect of the fusion protein was during RNA elongation, not at the level of initiation, resembling the faithfully initiated but incomplete transcripts produced with purified factors in the absence of SII. Similarly, monoclonal antibody 2-7B, which reacts with the RNA polymerase II region represented in the fusion protein, inhibited specific transcription at the level of elongation in a whole-cell extract. Both monoclonal antibody 2-7B and the fusion protein, although unable to inhibit purified RNA polymerase II in a nonspecific transcription assay, selectively blocked the stimulation elicited by transcription elongation factor SII on the activity of the purified enzyme in vitro. This suggests that the fusion protein traps the SII in nonstimulatory interactions and that antibody 2-7B inhibits SII binding to RNA polymerase II. Thus, this suggests that an SII-binding contact required for specific RNA elongation resides within the fifth exon region of the largest RNA polymerase II subunit.

Amino Acid Sequence↗
PubMed1987

Purine triphosphate beta-gamma bond hydrolysis requirements for RNA polymerase II transcription initiation and elongation.

RNA polymerase II-specific transcription requires, in addition to auxiliary protein factors, the hydrolysis of the beta-gamma phosphate bond of ATP. The nonhydrolyzable analog of ATP, imidoadenosine triphosphate does not suffice for specific in vitro transcription (Bunick, D., Zandomeni, R., Ackerman, S., and Weinmann, R. (1982) Cell 29, 877-886), although it can be incorporated into RNA. The experiments presented here suggest two energy-dependent steps in RNA polymerase II transcription. One of these steps is required at, or close to, the point of initiation, as determined by 5' end primer extension analysis. In vitro transcription occurs efficiently in vitro when imidoadenosine triphosphate is supplemented with dATP to fulfill the energy requirement. In the presence both of imidoadenosine triphosphate and imidoguanosine triphosphate, the concentration of dATP required for transcription initiation is dramatically increased. This suggests that ATP and GTP are co-substrates in transcription initiation, supporting the role of protein kinase II in this process (Zandomeni, R., Zandomeni, M. C., Shugar, D., and Weinmann, R. (1986) J. Biol. Chem. 261, 3414-3419). The concentration of dATP required for maximal initiation is inadequate for the production of full-length transcripts, suggesting a second energy-dependent step in the RNA elongation process. Since the elongation step is unaffected by the presence of imidoguanosine triphosphate, GTP beta-gamma phosphate bond hydrolysis appears to be required only for initiation.

Adenosine Triphosphate↗
PubMed1987

Purification and functional characterization of transcription factor SII from calf thymus. Role in RNA polymerase II elongation.

SII was purified from calf thymus tissue to apparent homogeneity by a rapid procedure. The 38-kDa protein stimulated RNA synthesis by purified calf thymus RNA polymerase II 4-fold. The calf thymus SII had similar chromatographic properties and molecular size and cross-reacted immunologically with antibodies to mouse SII (Sekimizu, K., Nakanishi, Y., Mizuno, D., and Natori, S. (1979) Biochemistry 18, 1582-1588). We have substituted the purified calf thymus SII for the partially purified HeLa transcription factor IIS fraction in a HeLa (human) transcription system reconstituted with purified factors and RNA polymerase II. The purified protein stimulated specific transcription from the adenovirus 2 major late promoter by increasing the efficiency of the elongation reaction.

Animals↗