Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytoplasmic domain of the erythropoietin receptor (EpoR) contains a membrane-distal region that is dispensable for mitogenesis but is required for the recruitment and tyrosine phosphorylation of a variety of signaling proteins. The membrane-proximal region of 96 amino acids is necessary and sufficient for mitogenesis as well as Jak2 activation, induction of c-fos, c-myc, cis, the T-cell receptor gamma locus (TCR-gamma), and c-pim-1. The studies presented here demonstrate that this region is also necessary and sufficient for the activation of Stat5A and Stat5B. The membrane-proximal domain contains a single tyrosine, Y-343, which when mutated eliminates the ability of the receptor to couple Epo binding to the activation of Stat5. Furthermore, peptide competitions demonstrate that this site, when phosphorylated, can disrupt Stat5 DNA binding activity, consistent with a role of Y-343 as a site of recruitment to the receptor. Cells expressing the truncated, Y343F mutant (a mutant with a Y-to-F alteration at position 343) proliferate in response to Epo in a manner comparable to that of the controls. However, in these cells, Epo stimulation does not induce the appearance of transcripts for cis, TCR-gamma, or c-fos, suggesting a role for Stat5 in their regulation.
Mol Cell Biol 1996 Apr
PMID:Erythropoietin induces activation of Stat5 through association with specific tyrosines on the receptor that are not required for a mitogenic response. 865 37

In order to investigate whether the pulmonary response to helminth antigens mimics that seen in allergic inflammation of the airways, we have examined the phenotypic characteristics of lymphocytes and eosinophils recruited to the airways following Nippostrongylus brasiliensis (N.b.) infection. Specifically, the cellular response was divided into an early and a late phase. During the early response there was a small but significant increase in neutrophil numbers recovered by bronchoalveolar lavage (BAL). Phenotypic analysis of BAL leukocytes revealed an early rise in the percentage of BAL lymphocytes expressing the naive T cell markers CD45RB and L-selectin, and the activation marker IL-2R. In addition, during the early response, there was an increased percentage of lymphocytes expressing the gamma delta TCR, but not the alpha beta TCR. In contrast, the late response was marked by a much larger accumulation, in the lungs and BAL, of memory CD4+ T lymphocytes and an influx of small, hypodense eosinophils which produced LTB4 and LTC4 on stimulation with calcium ionophore. At this time there was a substantial increase in the number of T lymphocytes and eosinophils expressing ICAM-1 and the integrins VLA-4 and LFA-1, implicating these adhesion molecules in inflammatory cell recruitment to the airways. We conclude that the pattern and phenotypic characteristics of the cellular recruitment seen following N.b. infection resemble those seen in early- and late-phase allergic inflammation of the airways in asthma, and therefore N.b. may be used to model these aspects of the disease.
Am J Respir Cell Mol Biol 1996 Jul
PMID:Phenotypic analysis of airway eosinophils and lymphocytes in a Th-2-driven murine model of pulmonary inflammation. 867 19

This work describes protocols for the production of single-chain antibody and T-cell receptor fragments in E. coli. A choice of methods is given for the purification of the recombinant fragments that rely on the use of either immunoaffinity or metal chelate affinity chromatography. The TCR fragments may have to be denatured and refolded before the fragments attain their proper conformation.
Mol Biotechnol 1995 Dec
PMID:Expression and purification strategies for the production of single-chain antibody and T-cell receptor fragments in E. coli. 868 Sep 30

T-cell receptor-gamma gene rearrangements provide specific clonal markers for a variety of lymphoid malignancies. T-cell receptor gene rearrangements in patients with cutaneous T-cell lymphoma were examined using conventional Southern blot analysis and a newly developed polymerase chain reaction (PCR)-based technique. The oligoprimers amplified a rearranged V gamma and J gamma segment (including the N region) of the T-cell receptor-gamma gene, and products were resolved using high-resolution nondenaturing polyacrylamide gel electrophoresis. Our results demonstrated concordance between the two techniques in 10 patients with cutaneous T-cell lymphomas (including nine cases of C beta and one case of delta 2 TCR gene rearrangements) and 10 negative controls. In the present study, we have shown that this PCR-based method provides a highly sensitive, specific technique for the detection of T-cell clones of both the alpha beta and gamma delta varieties and could be used in both fresh and formalin-fixed, paraffin-embedded tissues. It is estimated that this PCR-based technique is 10 to 50 times more sensitive than conventional Southern blot analysis in the detection of small T-cell clones.
Diagn Mol Pathol 1996 Jun
PMID:A rapid polymerase chain reaction-based technique for detecting clonal T-cell receptor gene rearrangements in cutaneous T-cell lymphomas of both the alpha beta and gamma delta varieties. 872 99

We have sequenced the TCRs from Ld-specific alloreactive T cell hybridomas, whose reactivities we have found to be quite representative of those of a primary dm2 anti-BALB/cJ mixed lymphocyte reaction. We find V beta 6, V beta 7, V beta 8 and V beta 10 gene segments. V alpha usage is diverse, although closely related to that from peptide-specific Ld-restricted CTLs. V alpha-V beta selection provides evidence of preferential pairing. Amino acid frequency analysis shows that the alpha CDR2 region is rich in charged amino acids, in contrast to the beta CDR2 region. Our data suggests the beta chain may be more immunoglobulin-like than the alpha chain, and that charge complementarity may be important in TCR-MHC interactions. We do not consider our results to be contradictory to those previously reported but rather they may represent an early, more diverse response.
Mol Immunol 1996 Jun
PMID:H-2Ld-alloreactive T cell hybridomas utilize diverse V alpha and V beta T cell receptor chains. 881 Oct 70

A well-known consequence of TCR stimulation in proliferating T cells is cell death by apoptosis. We have previously shown that the extent of tyrosine phosphorylation of TCR zeta, CD3 gamma, and CD3 epsilon subunits in proliferating CD4-CD8+ T cells after TCR stimulation was decreased when compared to similarly stimulated naive T cells expressing the same TCR. Furthermore, these differences correlated with a decrease in the specific kinase activity of p56lck and p59fyn, with a corresponding increase in the specific kinase activity of p50rsk, a negative regulator of src-family tyrosine kinases. In this study we determined whether kinases that bind tyrosine phosphorylated TCR zeta chain were differentially regulated in naive and proliferating cells. Chemically synthesized cytoplasmic domains of the TCR zeta chain were fully phosphorylated in vitro with p56lck and used to precipitate TCR zeta binding proteins in naive and proliferating cells. Using this method we found that both ZAP-70 and p72syk bound tyrosine phosphorylated TCR zeta very efficiently. More interestingly, p72syk was found to be expressed only in naive but not proliferating cells. Kinetic studies indicate that more than 48 hr of activation was required for ceasation of p72syk expression. We also showed that the inability to detect p72syk expression in proliferating cells was not due to its translocation to cytoskeletal compartments in proliferating cells. We propose that the differential regulation of ZAP-70 and p72syk in naive and proliferating cells may contribute to the uncoupling of the TCR signaling pathway from downstream signaling events leading to distinct functional outcomes in these two cell types after TCR stimulation.
Mol Immunol 1996 Jul
PMID:Differential regulation of p72syk expression in naive and proliferating CD4-CD8+ T cells. 884 15

Large-cell anaplastic lymphomas (LCAL) are characterized by their distinctive morphology together with expression of the CD30 antigen. In addition, a chromosomal translocation, t(2;5) (p23; q35), can be detected in most cases. A significant proportion of LCALs carry rearrangements of the T-cell receptor-gamma (TCR-gamma) locus and display a T-cell phenotype. In about a third of the cases, another type of non-Hodgkin-lymphoma precedes LCAL. Early transformations of non-Hodgkin's lymphoma into LCAL might escape clinical detection in a significant number of cases. The existence of clonally related lymphoid cells within the lymph node infiltrates must be claimed in these cases. Recently, a small-cell-predominant variant of LCAL was described in which only few large tumor cells expressing the CD30 antigen are found together with numerous small lymphocytes, which are frequently CD30-. This observation in particular prompted us to investigate the clonal relationship of the tumor cell compartment and admixed small lymphocytes in one case of common LCAL with T-cell genotype. For this purpose, we chose to amplify rearranged TCR-gamma sequences from single cells isolated from immunostained frozen sections by using a micromanipulator. A total of 119 cells were investigated. Amplification products were obtained in 17 of 79 CD3+ cells, 12 of 30 CD30+ cells, and three of 10 CD20+ cells. The nucleotide sequences were determined in 28 cells by nonradioactive sequencing. In 11 CD30+ cells, the predominant rearrangement of TCR-gamma was identified. No clonal diversity was observed. The small CD3+ lymphocytes were unrelated to the anaplastic CD30+ tumor cells. This report describes a method to analyze rearrangements of the TCR-gamma in single cells isolated from immunostained frozen sections. Application of this technique revealed an absence of clonal diversity in a case of LCAL and documented the polyclonal nature of admixed small CD3+ lymphocytes.
Diagn Mol Pathol 1996 Mar
PMID:Single-cell analysis of T-cell receptor-gamma rearrangements in large-cell anaplastic lymphoma. 891 40

In the adult mouse, the earliest thymocytes are derived from bone marrow-resident T lymphocyte precursor (pre-T) cells that immigrate to the thymus. There they undergo maturation through a series of developmental steps that include rearrangement and expression of the TCR genes, positive and negative selection, and functional maturation. Although these intrathymic processes have been extensively characterized, little is known about the T cell-specific events that take place in the bone marrow microenvironment. Of particular interest are the events surrounding transcription and rearrangement of the various TCR chains that are required for functional TCR expression. We have previously reported the transcription of incompletely rearranged TCR beta genes in pre-T cell-containing fractions of adult bone marrow. Here we demonstrate that the TCR gamma chain genes are also transcriptionally active in these cells. Like the TCR beta transcripts, TCR gamma transcripts are sterile, originating from unrearranged gamma loci. Interestingly, both RAG-1 and RAG-2 transcripts were also detected in this cell fraction, suggesting that sterile TCR transcription might be dependent upon the presence of a functional recombinase system. However, both C beta and C gamma sterile transcripts could be detected from the same bone marrow cell population isolated from RAG-1 gene deficient mice. Therefore, the expression of TCR genes can initiate at the earliest stages of T cell development, prior to exposure to the thymic microenvironment, and a functional recombinase system is not required for the production of these sterile TCR transcripts.
Mol Immunol 1996 Aug
PMID:Pre-thymic transcription of TCR genes by adult murine bone marrow cells. 896 Jan 20

The bacteriophage P1 Cre/loxP site-specific recombination system is a useful tool for engineering chromosomal changes in animal cells. Transient expression of the Cre recombinase gene directly introduced into fertilized eggs by pronuclear injection has been reported to provide an efficient method of transgene modulation in fertilized eggs. In the present study, we examined the efficacy of this method to remove loxP-flanked DNA sequences in a gene-targeted locus in fertilized eggs. We replaced a part of the T-cell receptor gamma (TCR V gamma) locus with homologous sequences containing a loxP-flanked neogene in mouse embryonic stem (ES) cells by gene-targeting technique. The resulting ES cell clones containing the mutant allele (V gamma LNL) were used to generate chimeric mice by blastocyst injection. Eight male chimeras were bred with superovulated wild-type female mice. One hundred and seventy-six fertilized eggs were collected, and subjected to pronuclear injection of the Cre expression plasmid, pCAGGS-Cre, of a covalently closed circular form. Three out of 11 pups inherited the targeted V gamma locus. The inherited targeted allele of these 3 mice was shown to have undergone Cre-mediated recombination, resulting in a deletion of the loxP-flanked sequences (V gamma delta) as shown by Southern blot analysis of DNA from tail biopsies. All 3 founder mutant mice were capable of transmitting the V gamma delta locus to their offspring. The other 8 pups carried only wild-type alleles. There were no pups carrying the unrecombined V gamma LNL locus. Thus, the frequency of Cre-mediated recombination was 100% (3/3) with this method. In contrast, when closed circular pCAGGS-Cre plasmid was introduced into ES cells by electroporation, the recombination frequency of the V gamma LNL locus was 9.6%. These results indicated that our system based on transient expression of the Cre recombinase gene directly introduced into fertilized eggs by pronuclear injection provides a fast and efficient method for generating mutant mice with desired deletions or translocations in target genes.
Mol Reprod Dev 1997 Feb
PMID:Efficient removal of loxP-flanked DNA sequences in a gene-targeted locus by transient expression of Cre recombinase in fertilized eggs. 902 42

To understand better, the role of non-anchor residues of class I restricted T cell epitopes in class I binding and TCR stimulation, a panel of peptides was synthesized in which each of the non-anchor positions of the Db-restricted influenza peptide, ASNENMETM, was changed to each of the 20 natural amino acids (AAs). The relative affinity of all the peptides for Db was determined and their ability to stimulate anti-ASNENMETM cytotoxic T cell hybridomas was also assessed. The results illustrated that for Db binding, the AAs with the most solvent exposure had the smallest effect on binding. Changes at other positions affected binding to different degrees. Results for the recognition by the T cell hybridomas indicated that a peptide-MHC complex represents a multitude of epitopes, as each hybridoma recognized a different subset of peptides. Most changes in the highly solvent-exposed residues negatively affected recognition by all hybridomas while changes in other positions affected each hybridoma differently, independent of the direction of the side chain of the AA at that position. Furthermore, the use of saturating concentrations of low and high binding peptides showed that, as long as the class I-peptide complex is formed, the T-cell receptor does not differentiate between high and low binding peptides. This indicates that, although the stability of the class I-peptide complex is highly dependent on peptide affinity, the class I MHC conformation induced by low affinity peptides does not necessarily differ significantly from that induced by high affinity peptides. The results of peptide-class I recognition by one ASNENMETM-specific hybridoma was used to construct a peptide that differed from ASNENMETM at four of the nine residues, yet stimulated the hybridoma to a level comparable to ASNENMETM. In addition, peptides bearing the canonical Db-binding motif but unable to bind to the class I molecule with high affinity could be made to bind Db, by changing unfavorable AAs to favourable ones at appropriate positions. The extended motif determined was used to identify more accurately the peptides derived from Coxsakie b3 virus that would bind Db. It was also shown that some of the canonical characteristics of the peptide motif could be obviated and still obtain high affinity binding, provided optimal AAs, were present at secondary anchor positions.
Mol Immunol 1996 Dec
PMID:Role of non-anchor residues of Db-restricted peptides in class I binding and TCR triggering. 917 92


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