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 enhancer region of Akv murine leukemia virus contains the sequence motif ACAGATGG. This sequence is homologous to the E-box motif originally defined as a regulatory element in the enhancers of immunoglobulin mu and kappa genes. We have used double-stranded oligonucleotide probes, corresponding to the E box of the murine leukemia virus Akv, to screen a randomly primed lambda gt11 cDNA expression library made from mouse NIH 3T3 fibroblast RNA. We have identified seven lambda clones expressing DNA-binding proteins representing two different genes termed ALF1 and ALF2. The results of sequencing ALF2 cDNA suggests that we have recovered the gene for the basic-helix-loop-helix transcription factor A1, the murine analog of the human transcription factor E47. The cDNA sequence of ALF1 codes for a new member of the basic-helix-loop-helix protein family. Two splice variants of ALF1 cDNA have been found, differing by a 72-bp insertion, coding for putative proteins of 682 and 706 amino acids. The two ALF1 mRNAs are expressed at various levels in mouse tissues. In vitro DNA binding assays, using prokaryotically expressed ALF1 proteins, demonstrated specific binding of the ALF1 proteins to the Akv murine leukemia virus E-box motif ACAGATGG. Expression in NIH 3T3 fibroblasts of GAL4-ALF1 chimeric protein stimulated expression from a minimal promoter linked to a GAL4 binding site, indicating the existence of a transcriptional activator domain in ALF1.
Mol Cell Biol 1992 Aug
PMID:Murine helix-loop-helix transcriptional activator proteins binding to the E-box motif of the Akv murine leukemia virus enhancer identified by cDNA cloning. 132 36

Analysis of the p50 and p65 subunits of the NF-kappa B transcription factor complex has revealed that both proteins can interact with related DNA sequences through either homo- or heterodimer formation. In addition, the product of the proto-oncogene c-rel can bind to similar DNA motifs by itself or as a heterodimer with p50 or p65. However, these studies have used a limited number of known kappa B DNA motifs, and the question of the optimal DNA sequences preferred by each homodimer has not been addressed. Using purified recombinant p50, p65, and c-Rel proteins, optimal DNA-binding motifs were selected from a pool of random oligonucleotides. Alignment of the selected sequences allowed us to predict a consensus sequence for binding of the individual homodimeric Rel-related proteins, and DNA-protein binding analysis of the selected DNA sequences revealed sequence specificity of the proteins. Contrary to previous assumptions, we observed that p65 homodimers can interact with a subset of DNA sequences not recognized by p50 homodimers. Differential binding affinities were also obtained with p50- and c-Rel-selected sequences. Using either a p50- or p65-selected kappa B motif, which displayed differential binding with respect to the other protein, little to no binding was observed with the heterodimeric NF-kappa B complex. Similarly, in transfection experiments in which the selective kappa B binding sites were used to drive the expression of a chloramphenicol acetyltransferase reporter construct, the p65- and p50-selected motifs were activated only in the presence of p65 and p50/65 (a chimeric protein with the p50 DNA binding domain and p65 activation domain) expression vectors, respectively, and neither demonstrated a significant response to stimuli that induce NF-kappa B activity. These findings demonstrate that interaction of both subunits of the heterodimeric NF-kappa B complex with DNA is required for DNA binding and transcriptional activation and suggest that transcriptional activation mediated by the individual rel-related proteins will differ dramatically, depending on the specific kappa B motifs present.
Mol Cell Biol 1992 Oct
PMID:Selection of optimal kappa B/Rel DNA-binding motifs: interaction of both subunits of NF-kappa B with DNA is required for transcriptional activation. 140 30

Several lines of evidence link the protein tyrosine kinase p59fyn to the T-cell receptor. The molecular basis of this interaction has not been established. Here we show that the tyrosine kinase p59fyn can associate with chimeric proteins that contain the cytoplasmic domains of CD3 epsilon, gamma, zeta (zeta), and eta. Mutational analysis of the zeta cytoplasmic domain demonstrated that the membrane-proximal 41 residues of zeta are sufficient for p59fyn binding and that at least two p59fyn binding domains are present. The association of p59fyn with the zeta chain was specific, as two closely related Src family protein tyrosine kinases, p60src and p56lck, did not associate with a chimeric protein that contained the cytoplasmic domain of zeta. Mutational analysis of p59fyn revealed that a 10-amino-acid sequence in the unique amino-terminal domain of p59fyn was responsible for the association with zeta. These findings support evidence that p59fyn is functionally and structurally linked to the T-cell receptor. More importantly, these studies support a critical role for the unique amino-terminal domains of Src family kinases in the coupling of tyrosine kinases to the signalling pathways of cell surface receptors.
Mol Cell Biol 1992 Dec
PMID:p59fyn tyrosine kinase associates with multiple T-cell receptor subunits through its unique amino-terminal domain. 144 76

We developed a novel genetic method for finding functional regions of a protein by the analysis of chimeras formed between homologous proteins. Sets of chimeric genes were made by intramolecular homologous recombination in a linearized plasmid DNA carrying both recA genes of Escherichia coli and Pseudomonas aeruginosa. A recBCsbcA strain of E. coli was used for isolation of plasmids carrying recombinants between these genes. Examination of properties of E. coli strains deleting the recA gene and carrying a plasmid with a chimeric gene shows that chimera formation at certain positions inactivates a RecA function. Frequently, all chimeras with a junction in a certain region of the protein inactivate a function. Rather than a direct effect of the presence of the junction at a particular position, mismatching of the regions both sides of the junction that are derived from the different species is responsible for the inactivation. For a chimeric protein to be functional, certain pairs of sequences in different regions of the protein must derive from the same parent. Four pairs of such sequences were found: two are involved in activities for genetic recombination and for resistance to ultraviolet light irradiation and the others in formation of active oligomers. Regions defined by these sequences are located in the looped regions of the protein. A pair of regions may co-operate to form a functional folded structure.
J Mol Biol 1992 Aug 05
PMID:Functional structures of the recA protein found by chimera analysis. 150 20

Chromosomal abnormalities affecting proto-oncogenes are frequently detected in human cancer. Oncogenes of the myc family are activated in several types of tumors as a result of gene amplification or chromosomal translocation. We have recently found the L-myc gene involved in a gene fusion in small-cell lung cancer (SCLC). This results in a chimeric protein with amino-terminal sequences from a novel gene named rif joined to L-myc. Here we present a preliminary structural characterization of the rlf-L-myc fusion gene, which has been found only in cells with an amplified L-myc gene. In addition, we have used somatic cell hybrids to assign the normal rlf locus to the same chromosome (chromosome 1) on which L-myc resides. Finally, we have been able to establish a physical linkage between rif and L-myc with pulsed-field gel electrophoresis. Our results demonstrate that normal rlf and L-myc genes are separated by less than 800 kb of DNA. Thus, the rlf-L-myc gene fusions are due to similar but not identical intrachromosomal rearrangements at 1p32. The presence of independent genetic lesions that cause the formation of identical chimeric rlf-L-myc proteins suggests a role for the fusion protein in the development of these tumors.
Mol Cell Biol 1991 Aug
PMID:Intrachromosomal rearrangements fusing L-myc and rlf in small-cell lung cancer. 164 86

The hybrid gene of influenza virus hemagglutinin (HA) of the H1-subtype, carrying the sequence coding for the fragment of H3-subtype antigenic site B, was constructed. The product of expression of this gene in E. coli was obtained as a fusion protein with beta-galactosidase. The chimeric protein was shown to retain the antigenic properties of HA of H1-subtype and to interact specifically with antibodies against the synthetic peptide corresponding to the B site fragment of HA of the H3-subtype.
Mol Biol (Mosk)
PMID:[Construction and expression in Escherichia coli of a gene of hybrid hemagglutinin H1-H3 of influenza virus]. 169 68

By gene-engineering technique a chimeric protein made up of fragments of Staphylococcus aureus protein A and . Pseudomonas aeruginosa exotoxin A has been constructed. The chimeric protein was shown to preserve features characteristic of its both constituents--it ADP-ribosylates elongation factor 2 and binds to Ig. Cytotoxic properties of the chimeric protein were studied in two model systems. Treatment of target cells in both systems was performed successively with antibodies against corresponding antigens and after washing--with recombinant chimeric toxin which bound to antibodies on the surface of target cells. In the first model system human B-lymphoma cells (Daudi line) carrying Ig molecules on their surface were treated with polyclonal antibodies against human Ig L-chains. In the other system, human T-lymphoma cells (Jurkat line) were treated successively with monoclonal antibodies against cell surface CD5 antigen and further on--with polyclonal antibodies against mouse Ig. In both systems, only a slight inhibition of the target cells' growth was registered. The probable reasons of low cytotoxic activity of the chimeric protein and prospects of increasing it are discussed.
Mol Biol (Mosk)
PMID:[Cytotoxic properties of a recombinant hybrid of the A protein of Staphylococcus aureus with a fragment of exotoxin A of Pseudomonas aeruginosa]. 175 51

Steroid induction of responsive genes functions through the synergistic activity of steroid receptor-binding sequences with adjacent transcription factor-binding sites. To analyze the mechanism of synergy we tested different human glucocorticoid receptor mutants for synergistic function with another transcription factor in comparison with intrinsic trans-activation obtained with a single receptor binding site (glucocorticoid response element). Multiple domains were found to be involved in synergistic activity of the glucocorticoid receptor with the CACCC box factor. Deletions within the N-terminal receptor half affected simultaneously intrinsic trans-activation and synergism. However, deletion of the hormone-binding domain mainly impaired synergism rather than intrinsic trans-activation, clearly showing that this domain synergizes by a mechanism independent of intrinsic activation. A chimeric protein where the DNA-binding domain of the glucocorticoid receptor was replaced by that of the yeast GAL4 protein also showed functional synergism. These data suggest that some of the receptor domains outside the DNA-binding domain synergize by their intrinsic trans-activating property, but the hormone-binding domain contributes to synergism by a different mechanism.
Mol Endocrinol 1991 Oct
PMID:Multiple domains of the glucocorticoid receptor involved in synergism with the CACCC box factor(s). 177 33

We have isolated a hybrid gene, composed of the first 455 nucleotides of hisP and nucleotides 275-1107 of malK, the genes coding for the nucleotide-binding components of the high-affinity transport systems for histidine and maltose in Salmonella typhimurium, respectively. The fusion had occurred by recombination within 11 homologous base pairs located between the two DNA fragments. In the chimeric protein peptidic motifs A and B, proposed to be part of the nucleotide-binding fold, originate from HisP and MalK, respectively. Plasmid pES42-39, harbouring the hybrid gene, was shown to complement only a malK mutation but failed to complement a hisP deletion mutation. The chimeric protein was identified by immunoblotting as a protein with an apparent molecular mass of 49kDa. Removal of the C-terminal 77 amino acid residues from the chimeric protein resulted in the loss of function in transport. In contrast, 51 amino acid residues could be removed from the C-terminus of wild-type MalK without any effect. Upon overproduction the chimeric protein, as wild-type MalK, inhibited expression of the malB regulon. However, both truncated proteins, when overproduced, did not exhibit this activity. Based on these results, a tentative model of the functional domains of MalK is presented.
Mol Microbiol 1991 Jun
PMID:A chimeric nucleotide-binding protein, encoded by a hisP-malK hybrid gene, is functional in maltose transport in Salmonella typhimurium. 178 92

Although the Rap1A protein resembles the oncogenic Ras proteins both structurally and biochemically, Rap1A exhibits no oncogenic properties. Rather, overexpression of Rap1A can reverse Ras-induced transformation of NIH 3T3 cells. Because the greatest divergence in amino acid sequence between Ras and Rap1A occurs at the COOH terminus, the role of this domain in the opposing biological activities of these proteins was examined. COOH-terminal processing and membrane association of Rap1A were studied by constructing and expressing a chimeric protein (composed of residues 1 to 110 of an H-Ras activated by a Leu-61 mutation attached to residues 111 to 184 of Rap1A) in NIH 3T3 cells and a full-length human Rap1A protein in a baculovirus-Sf9 insect cell system. Both the chimeric protein and the full-length protein were synthesized as a 23-kDa cytosolic precursor that rapidly bound to membranes and was converted into a 22-kDa form that incorporated label derived from [3H]mevalonate. The mature 22-kDa form also contained a COOH-terminal methyl group. Full-length Rap1A, expressed in insect cells, was modified by a C20 (geranylgeranyl) isoprenoid. In contrast, H-Ras, expressed in either Sf9 insect or NIH 3T3 mouse cells contained a C15 (farnesyl) group. This suggests that the Rap1A COOH terminus is modified by a prenyl transferase that is distinct from the farnesyl transferase that modifies Ras proteins. Nevertheless, in NIH 3T3 cells the chimeric Ras:Rap1A protein retained the transforming activity conferred by the NH2-terminal Ras61L domain. This demonstrates that the modifications and localization signals of the COOH terminus of Rap1A can support the interactions between H-Ras and membranes that are required for transformation.
Mol Cell Biol 1991 Mar
PMID:The COOH-terminal domain of the Rap1A (Krev-1) protein is isoprenylated and supports transformation by an H-Ras:Rap1A chimeric protein. 189 9


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