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Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat Aviv, Tel-Aviv, Israel.
The tumor suppressor gene p53 is mutated in more than half of human tumors. One important characteristic of p53 mutants is their accumulation in the nucleus of cancer cells. Thus, reactivation of mutant p53 proteins may trigger massive apoptosis in tumor cells. Pharmacologic methods are currently under development to induce mutant p53 proteins to resume their wild-type function. We have identified a human single-chain Fv fragment, designated as transcriptional transactivation and apoptosis restoring (TAR1), which specifically and with high affinity binds to mutant p53 and restores its wild-type active conformation. Binding of TAR1 to mutant p53 induced transcriptional transactivation of p53 target genes and down-regulation of mutant p53 transcriptional target genes. TAR1 treatment induced apoptosis in a variety of cell lines endogenously expressing p53 carrying different point mutations DNA contact or structural p53 mutants. Moreover, in an animal model of mice carrying human xenografts, TAR1 induced tumor regression with no apparent deleterious side effects. Thus, it may be considered as a potential candidate for anticancer treatment, targeting tumors with mutant p53.
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Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Israel. orgad@post.tau.ac.il
Here, we describe the biological activity of ME1, a mouse single chain Fv fragment (scFv) against the common epitope of mutant p53, which is efficiently expressed in mammalian cells. We found that in vivo interaction of the conformational p53 mutant R175H protein with the scFv resulted in the acquisition of wild-type p53 characteristics, manifested in trans-activation of p21, as well as induction of apoptosis. Moreover, antibody binding leads to abrogation of the mutant p53 mediated "gain of function" as estimated by downregulation of EGR-1, a transcriptional target of mutant p53. These findings suggest that the scFv restores wild-type properties to mutant p53.
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Neurobiology Department, The Weizmann Institute for Science, Rehovot, Israel.
The tetanic (tta; X.-52.6) mutation has been isolated on the basis of its sensitivity to extradoses of the normal Shaker gene complex (ShC) where the K+ channel la is encoded. The mutant shows up to threefold elevation of the membrane bound protein phosphatase type 1 (PP1) activity in body extracts, probably due to reduced levels of the PP1 specific inhibitor 2 (I-2). By contrast, PP1 activity in the head is only half of the normal value. In addition, tta fails to perform normally in a negative reinforcement olfactory paradigm. The functional relationships between phosphorylation, K+ currents, phosphatase activity and modulation of synaptic activity during learning and memory are discussed in the light of their possible genetic links.
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Division of Transplantation Immunology; Tissue typing lab, Sheba Medical Center, Tel Hashomer, Israel.
OBJECTIVE: Couples with consecutive recurrent miscarriages (CRM) are not generally believed to share more HLA antigens with their spouses than expected by chance. This paper attempted to determine the situation in patients with five or more miscarriages. METHODS: The number of shared HLA class I and class II antigens, HLA phenotype, and the ability to mount an antibody response in a large cohort of 425 couples with CRM was assessed, according to whether the patient had three or four, or five or more miscarriages. RESULTS: There was no significant difference in the frequency of shared HLA antigens in women with five or more miscarriages when compared to three or more miscarriages or control patients. No specific HLA antigen or phenotype was associated with CRM in male or female partners of either group. The number of shared antigens did not influence ability to develop anti paternal antibodies (APA). Moreover, HLA antigen sharing had no influence on the subsequent pregnancy after paternal leucocyte immunization. CONCLUSION: Class I and Class II HLA antigens are not diagnostic for immunologically mediated abortion, do not predict the ability to mount an antibody response, or the outcome of a subsequent pregnancy.
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Transplantation Division, Biomolecular Section, CF Screening Unit, Sheba Medical Center, Tel Hashomer, Israel. sorgad@yahoo.com
The aim of this study was to evaluate the screening policies of cystic fibrosis (CF) in the Jewish population. The prevalence of mutations that account for CF in Israel have been defined in the past by determining the frequency of CF mutations in affected individuals. This study is a population-based study and is, therefore, different from previous patient-based studies. We found that the CF mutations D1152H, W1089X, and 405 + IG-->A were present in some ethnic groups in which no CF patients carrying these mutations were reported. These facts necessitate a reevaluation of the screening policy regarding the ethnic groups in Israel. We studied 9,430 healthy Jewish Israeli individuals of 36 countries of origin. The prevalence of CF mutations was 1:19, 1:19, 1:28, and 1:42 for the Ashkenazi, Sephardi, North African, and Eastern Jews, respectively. CF mutations were identified in 374 (4.0%) individuals. These included 173 (46.3%) carriers of the W1282X mutation; 110 (29.4%) found to carry delF508; 23 (6.1%) who carried G542X; 22 (5.9%) who carried 3849 + 10Kb (C-->T; 20 (5.3%) who carried D1152H; 10 (2.7%) who carried N1303K; 11 (2.9%) who carried 405 + IG-->A; 4 (1.1%) who carried W1089X; and one (0.3%) who carried S549R. No carriers were detected for the 1717-1G-->A, G85E, and T360K mutations, which were tested for in 7,383, 1,558, and 41 individuals, respectively.
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Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv 69978, Israel.
The courtless (col) mutation disrupts early steps of courtship behavior in Drosophila males, as well as the development of their sperm. Most of the homozygous col/col males (78%) do not court at all. Only 5% perform the entire ritual and copulate, yet these matings produce no progeny. The col gene maps to polytene chromosome band 47D. It encodes two proteins that differ in their carboxy termini and are the Drosophila homologs of the yeast ubiquitin-conjugating enzyme UBC7. The col mutation is caused by an insertion of a P element into the 3' UTR of the gene, which probably disrupts translational regulatory elements. As a consequence, the homozygous mutants exhibit a six- to sevenfold increase in the level of the COL protein. The col product is essential, and deletions that remove the col gene are lethal. During embryonic development col is expressed primarily in the CNS. Our results implicate the ubiquitin-mediated system in the development and function of the nervous system and in meiosis during spermatogenesis.
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Division of Transplantation Immunology, Tissue Typing Laboratory, Sheba Medical Center, Tel Hashomer 52621, Israel.
Anti-paternal antibodies directed towards paternal leukocytes have been used to predict the prognosis for the subsequent pregnancy in women with consecutive recurrent miscarriages (CRM) and also to determine if the patient has become immune after paternal leukocyte immunization. The predictive value is controversial, as these antibodies are not essential for pregnancy to develop, and only occur in a minority of parous women. This study tried to determine the predictive value of these antibodies when assessed separately for women with five or more abortions and compared to women with three or four abortions. The patients were assessed separately so that the higher live birth rate in the latter group would not obscure meaningful results in the former group with a poor prognosis. Antibody production, whether spontaneous, or induced by immunization, raised the live birth rate in primary and tertiary aborters with three, four, five or more abortions. Anti-paternal antibodies increased the proportion of live births from 18.5 to 53. 7%(P </= 0.01) and from 44.4 to 67.5%(P </= 0.001) in primary aborters with >/= 5 CRM and 3-4 CRM respectively. Both immunization with paternal leukocytes per se and the ability to express anti-paternal antibodies were associated with an increased proportion of live births in the next pregnancy. Multivariate analysis showed that that the odds ratio for a live birth was approximately four times greater in women who were immunized and produced anti-paternal antibodies than in control patients. The lack of anti-paternal antibodies at initial testing could serve as a marker for the benefit of immunization with paternal leukocytes; the subsequent presence as a prognostic marker for the subsequent pregnancy.
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Department of Plant Sciences Tel Aviv University, 69978, Tel Aviv, Israel.
The COP9 signalosome (originally described as the COP9 complex) is an essential multi-subunit repressor of light-regulated development in plants [1][2]. It has also been identified in mammals, though its role remains obscure [3][4][5]. This complex is similar to the regulatory lid of the proteasome and eIF3 [5][9][10][11][12] and several of its subunits are known to be involved in kinase signaling pathways [4][6][7][8]. No proteins homologous to COP9 signalosome components were identified in the Saccharomyces cerevisiae genome, suggesting that the COP9 signalosome is specific for multi-cellular differentiation [13]. In order to reveal the developmental function of the COP9 signalosome in animals, we have isolated Drosophila melanogaster genes encoding eight subunits of the COP9 signalosome, and have shown by co-immunoprecipitation and gel-filtration analysis that these proteins are components of the Drosophila COP9 signalosome. Yeast two-hybrid assays indicated that several of these proteins interact, some through the PCI domain. Disruption of one of the subunits by either a P-element insertion or deletion of the gene caused lethality at the late larval or pupal stages. This lethality is probably a result of numerous pleiotropic effects. Our results indicate that the COP9 signalosome is conserved in invertebrates and that it has an essential role in animal development.
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Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Israel.
We describe six recessive autosomal male sterile mutations in Drosophila, generated by mobilization of single P-elements, exhibiting abnormal male courtship behavior. Detailed analysis of courtship behavior elicited by virgin wild type females indicated that five of the six mutants are affected in the early steps of courtship. The sixth mutant is blocked at the step of attempted copulation which occurs later in the courtship sequence. All of the mutants have normal olfactory responses and normal locomotor activity. No defect in the visual modality has been observed for the five mutants affected in the initiation of courtship. The mutant blocked at attempted copulation lacks the 'on' and 'off' transients, but this appears to be due to genetic background rather than the mutation itself. Abnormal spermatogenesis was observed in five of the mutants. Spermatogenic defects vary and include lesions in the proliferation of the germline, in meiosis, and in the differentiation and maturation of the spermatids into motile sperm.
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2012-05-23 07:22:12 © BioInfoBank Institute