UNIPROT:Q07644 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UNIPROT:Q07644 (polypeptide)
72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was previously shown that virus-specific polypeptides made in HEp-2 cells infected with herpes simplex 1 form three groups designated alpha, beta, and gamma whose synthesis is coordinately regulated and sequentially ordered. This report shows that one or more functional alpha polypeptides are necessary to turn on the synthesis of beta and gamma groups, and conversely, one or more polypeptides in the latter groups turn off the synthesis of alpha polypeptides. Specifically, infected cells maintained in medium containing either canavanine, an analogue of arginine, or azetidine-2-carboxylic acid an analogue of proline and hydroxyproline, synthesized alpha polypeptide at rates comparable to maximal rates in untreated infected cells but did not undergo the normal transition to beta and gamma polypeptide synthesis. The transition to gamma polypeptide synthesis and shut-off of synthesis of earlier polypeptide groups proceeded normally if addition of canavanine was delayed until at least 4-5 hr after infection. Addition of canavanine after the onset of beta and gamma polypeptide synthesis, i.e., between 2 and 3.5 hr after infection, resulted in sustained, simultaneous synthesis of all three polypeptide groups, a phenomenon not seen in untreated infected cells. Canavanine-treated infected cells, synthesizing alpha polypeptides, recovered the capacity to make beta and gamma polypeptides after removal of the analogue, but only after a 1-to 2-hr delay compared with infected untreated cells. The data indicate that the on and off controls inherent in the cascade regulation of viral polypeptide synthesis are mediated by one or more polypeptides in each group at transcriptional or post-transcriptional levels.
...
PMID:Regulation of herpesvirus macromolecular synthesis: sequential transition of polypeptide synthesis requires functional viral polypeptides. 16 3

This report concerns the stable viral RNA sequences that accumulate in HEp-2 cells infected with herpes simplex virus type 1. By hybridizing labeled total DNA and restriction endonuclease DNA fragments with excess unlabeled total nuclear and cytoplasmic RNA, we determined the genetic complexity of the RNA and we mapped the regions on the physical map of herpes simplex virus type 1 DNA that are homologous to the RNA. Our results show the following. (i) The viral RNAs accumulating in the nucleus and cytoplasm of cells infected and maintained in the presence of inhibitory concentrations of either cycloheximide or emetine were homologous to 33 and 12% of viral DNA, respectively. All of the fragments tested contained sequences homologous to nuclear RNA. However, only the fragments mapping between 0.00 and 0.18, and 0.53 and 1.00 map units contained sequences homologous to cytoplasmic RNA. (ii) The viral RNAs that accumulate in the nucleus and cytoplasm of cells infected and maintained in the presence of inhibitory concentrations of phoaphonoacetic acid were homologous to 39 and 26% of viral DNA, respectively. In this instance all of the fragments except those mapping between 0.42 and 0.53 map units contained sequences homologous to cytoplasmic RNA. (iii) The viral RNAs that accumulate in the nucleus and cytoplasm 8 h after infection were homologous to greater than 50 and 41%, respectively. All of the fragments tested contained sequences homologous to cytoplasmic RNA. (iv) The viral RNAs that accumulate in the nucleus and cytoplasm of cells infected and maintained in the presence of canavanine are homologous to 33 and 19% of viral DNA, respectively. All of the fragments tested contained sequences homologous to both nuclear and cytoplasmic RNAs. Our results indicate the following. First, there are at least three phases of transcription of viral DNA. Phase 1 does not require the synthesis of host cell or viral proteins. Phase 2 requires the synthesis of viral proteins made before the initiation of viral DNA synthesis. Phase 3 appears to be related to the initiation of viral DNA synthesis. Second, both the extent of transcription and the accumulation of viral RNA in the cytoplasm are tightly regulated. The genetic complexity of total RNA accumulating in infected cells increased in each successive phase. Moreover, the genetic complexity of nuclear RNA was invariably higher than that of cytoplasmic RNA in each phase. Lastly, the results of the studies on viral RNA accumulating in canavanine-treated cells reinforce the hypothesis made previously that more than one polypeptide in each of the alpha and beta polypeptide groups is involved in the transcription preceding the transitions from alpha to beta and beta to gamma polypeptide synthesis, respectively, and that canavanine selectively inactivated subsets of these polypeptides permitting only partial transitions from alpha to beta and beta to gamma to occur.
...
PMID:Regulation of herpesvirus macromolecular synthesis. VIII. The transcription program consists of three phases during which both extent of transcription and accumulation of RNA in the cytoplasm are regulated. 22 55

Fibrin obtained from the plasma of a patient having abnormal fibrogen Paris I contains normal alpha, beta, and gamma polypeptide chains as well as an abnormal gamma-chain (gammaParis I) of approximately 51,000 daltons molecular weight. Plasmic digestion of Paris I fibrogen and noncrosslinked fibrin yields both normal and abnormal Fragment D molecules, the latter having a higher negative charge and molecular weight than that liberated from normal fibrinogen and noncorsslinked fibrin. After disulfide bond reduction, an abnormal polypeptide chain of approximately 40,500 +/- 2,000 daltons molecular weight was demonstrated in the Paris I digests by dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Comparison with the electrophoretic pattern for reduced digests of normal substrates indicates that it is a gamma-chain remnant in the normal Fragment D. Although the carbohydrate content in the gamma-Paris I-chain is slightly higher than that in the normal gamma-chain, as measured by periodic acid-Schiff reagent (PAS) staining intensity, it is concluded that extra carbohydrate does not account for the high molecular weight of the gamma-Paris I-chain since the 40,500 dalton chain does not stain with PAS. Plasma digestion of Paris I crosslinked fibrin yields a large amount of Fragment D in addition to Fragment D-D ("D-dimer") and E molecules, in contrast to a digest of normal crosslinked fibrin, from which only the latter two fragments are formed. This finding suggests that the defect in fibrinogen Paris I derives from an abnormality in the carboxy-terminal region of the gammaParis I-chain, so that in the presence of Factor XIII, these chains are not crosslinked and Fragment D-D molecules are not liberated upon subsequent plasmic degradation. The data provide support for the previous conclusion that a longer than normal polypeptide chain sequence at the carboxy-terminal portion of the gammaParis I-chains accounts for the increased size of these chains relative to the normal gamma-chains and for the abnormal function of the intact fibrinogen Paris I molecule.
...
PMID:Plasmic degradation of fibrinogen Paris I. 97 44

Two membrane-bound nitrate reductases, NRA and NRZ, exist in Escherichia coli. Both isoenzymes are composed of three structural subunits, alpha, beta, and gamma encoded by narG/narZ, narH/narY and narI/narV, respectively. The genes are in transcription units which also contain a fourth gene encoding a polypeptide, delta, which is not part of the final enzyme. A strain which is devoid of, or does not express, the nar genes, was used to investigate the role of the delta and gamma polypeptides in the formation and/or processing of the nitrate reductase. When only the alpha and beta polypeptides are produced, an (alpha beta) complex exists which is inactive and soluble. When the alpha, beta and delta polypeptides are produced, the (alpha beta) complex is active with artificial donors such as benzyl viologen but is soluble. When the alpha, beta and gamma polypeptides are produced, the (alpha beta) complex is inactive but partially binds the membrane. It was concluded that the gamma polypeptide is involved in the binding of the (alpha beta) complex to the membrane while the delta polypeptide is indispensable for the (alpha beta) nitrate reductase activity. The activation by the delta polypeptide does not seem to involve the insertion of the redox centres of the enzyme since the purified inactive (alpha beta) complex was shown to contain the four iron-sulphur centres and the molybdenum cofactor, which are normally present in the native purified enzyme. The extreme sensitivity of this inactive complex to thermal denaturation or tryptic treatment favours the idea that the delta polypeptide promotes the correct assembly of the alpha and beta subunits. Although this corresponds to the definition of a chaperone protein this possibility has been rejected. In this study we have also demonstrated that the delta or gamma polypeptide encoded by one nar operon can be substituted successfully for by its respective counterpart from the other nar operon to give an active membrane bound heterologous nitrate reductase enzyme.
...
PMID:Involvement of the narJ or narW gene product in the formation of active nitrate reductase in Escherichia coli. 154 6

Two transgenic tobacco lines were genetically engineered to contain chimaeric genes encoding the glutamine synthetase (GS) gamma polypeptide of Phaseolus vulgaris (French bean), expressed from the cauliflower mosaic virus 35S promoter. One (MIT-1) contained two copies of a construct including the first 60 amino acids of the Nicotiana plumbaginifolia beta-F1 ATPase to target the GS polypeptide to the mitochondrion. The other (CYT-4) contained a single copy of a cytosolic GS construct. Leaves of in vitro plantlets expressed the constructs and contained a novel GS polypeptide, which assembled into active GS isoenzymes constituting about 25% of the total GS activity. In in vitro plantlets of MIT-1, but not CYT-4, the novel polypeptide was found to be associated with the mitochondria. Moreover in MIT-1, the size of the novel polypeptide was not that predicted of the precursor (44.9 kDa) but was about 39 kDa, the same size as the authentic GS gamma polypeptide in CYT-4. These results are consistent with the precursor being imported into the mitochondria and cleaved near the fusion junction between the two sequences. These experiments have therefore shown that the presequence of the beta-F1 ATPase has successfully targeted the GS gamma polypeptide to the mitochondria of transgenic tobacco where it has assembled into an active isoenzyme. However, in fully regenerated plants growing photoautotrophically in growth-room conditions, although the constructs were still expressed, the gamma polypeptide did not accumulate to the same levels as in in vitro plantlets and new isoenzyme activities were now barely detectable. Moreover in leaves of the mature MIT-1 plants, the gamma polypeptide was found to be associated with the insoluble fraction of the mitochondria. The results of these experiments are discussed.
...
PMID:Targeting of glutamine synthetase to the mitochondria of transgenic tobacco. 198 2

The dnaX gene (previously called dnaZX) of Escherichia coli has only one open reading frame for a 71-kDa polypeptide from which two distinct DNA polymerase III holoenzyme subunits, tau (71 kDa) and gamma (47 kDa), are produced. To determine how the gamma subunit is generated, we examined the influence of mutations in the dnaX gene on the pattern of tau and gamma production in overproducing cells. Important structural elements in dnaX mRNA include a stretch of six adenines (nucleotides 1425-1430), a stable hairpin structure (nucleotides 1437-1466), and a UGA stop codon in a -1 frame (nucleotides 1434-1436) between the stretch of adenines and the hairpin structure. Disruption of this stop codon generates a slightly larger gamma subunit, indicative of the use of a -1 stop codon farther downstream (nucleotides 1470-1472). These results suggest that a -1 frameshift during translation allows the use of this UGA codon to terminate translation of the gamma polypeptide. The amino acid composition, sequence, and mass spectra of a C-terminal peptide from mild digestion of the purified gamma protein with endoproteinase Lys-C confirms that this frameshift occurs at either of the two lysine codons in the region of the adenine stretch. Remarkable features of this frameshifting are its high frequency (i.e., about 80% in an overproducing cell) and the striking structural similarity to the frameshifting signal responsible for expression of the pol and pro genes in many retroviruses.
...
PMID:Translational frameshifting generates the gamma subunit of DNA polymerase III holoenzyme. 218 40

The interaction of interferon-alpha (IFN-alpha) with a specific cell-surface receptor elicits physiological changes that rely on rapid transcriptional activation of a group of IFN-alpha-stimulated genes (ISGs). The IFN-stimulated response element (ISRE), a conserved regulatory element of all ISGs, is the target for transcriptional activation by the positive regulator IFN-stimulated gene factor-3 (ISGF3). We reported previously that post-translational activation of ISGF3 in the cytoplasm of IFN-alpha-treated cells requires two cytoplasmic activities (ISGF3 alpha and ISGF3 gamma) to produce an ISRE-binding complex that accumulates in the nucleus. In this study, we show that these activities are actually distinct subunits of the ISGF3 complex, which associate through noncovalent interaction. Sedimentation analysis, protein renaturation, and photoaffinity cross-linking of enriched preparations of cytoplasmic ISGF3 alpha and ISGF3 gamma and of nuclear ISGF3 demonstrated that ISGF3 gamma was a 48-kD polypeptide with intrinsic, low-affinity DNA-binding activity. Four polypeptides of 48, 84, 91, and 113 kD bound to the ISRE in vitro; the larger three polypeptides most likely compose the ISGF3 alpha component. These ISGF3 alpha polypeptides were unable to bind DNA alone but formed a DNA-binding complex in conjunction with ISGF3 gamma. The resulting heteromeric complex had the same ISRE-binding specificity as the individual ISGF3 gamma polypeptide but approximately 25-fold higher affinity. Whereas ISGF3 gamma partitioned between the cytoplasm and nucleus in unstimulated cells, ISGF3 alpha was stimulated to translocate to the nucleus only following IFN-alpha treatment, resulting in preferential nuclear accumulation of both ISGF3 alpha and ISGF3 gamma as a stable ISGF3-ISRE complex. This regulated nuclear translocation of an activated transcription factor subunit maintained the specificity and rapidity of the IFN-alpha signaling pathway.
...
PMID:Interferon-alpha regulates nuclear translocation and DNA-binding affinity of ISGF3, a multimeric transcriptional activator. 224 73

We developed a monoclonal antibody (mAb) (9D7) against a synthetic peptide (P13K) selected from the deduced amino acid sequence of the constant region of the gamma chain of the murine T-cell antigen receptor (TCR) (amino acids 118-130). Using this mAb, we identified a putative second TCR expressed on peripheral blood lymphocytes from a patient with severe combined immunodeficiency (SCID) that were propagated in culture with recombinant interleukin 2 (rIL-2) and Con A. This mAb immunoprecipitated two polypeptide chains of 40 and 58 kDa under nonreducing conditions and of 40 and 56 kDa under reducing conditions from 125I-labeled denatured lysates of T3+ WT31- lymphocytes expanded in culture from a SCID patient. These polypeptide chains were not disulfide linked and were not present on human peripheral blood lymphocytes from normal donors cultured for 5 days with phytohemagglutinin or for 2 weeks with rIL-2 and polyclonal activators or on cells of the Jurkat lymphoblastoid human T-cell line. Chemical crosslinking of 125I-labeled cells followed by immunoprecipitation with anti-Leu-4 mAb under nonreducing or reducing conditions revealed that the 40- and 56-kDa polypeptide chains were associated with the T3 differentiation antigen. These results were confirmed by sequential immunoprecipitation with anti-Leu-4 mAb followed by 9D7 anti-P13K mAb. The 9D7 anti-P13K mAb immunoprecipitated two polypeptide chains of 43 and 64 kDa from denatured lysates of lymphocytes from a patient with severe common variable immunodeficiency (CVI) that were expanded in culture with rIL-2 and Con A. Thus, this second TCR may be composed of two polypeptide chains (gamma gamma'), both of which appear to be the product of the gamma-chain gene. These experiments were done with polyclonal cell populations. Cloned T3+ WT31- cell populations are required to determine whether this TCR contains two gamma polypeptide chains. In contrast, only one polypeptide chain of 56 kDa was immunoprecipitated by the 9D7 anti-P13K mAb from peripheral blood lymphocytes from a patient with mild CVI expanded in culture with rIL-2 and polyclonal activators. Using the same 9D7 anti-P13K mAb and immunoblotting analysis, we identified a 35 kDa gamma-chain polypeptide under reducing conditions expressed on purified L3T4- Lyt2- BALB/c mouse thymocytes. This gamma-chain TCR is disulfide linked and has a molecular mass of 80 kDa under nonreducing conditions.
...
PMID:Identification of a second T-cell antigen receptor in human and mouse by an anti-peptide gamma-chain-specific monoclonal antibody. 243 95

To obtain antibodies against the individual chains of the T cell receptor (TCR) complex, we have produced chimeric proteins containing domains from immunoglobulin (Ig) and TCR polypeptide chains. Basically, the Ig light chains were used as carriers for the TCR constant (C) region domains. The exons which encode the main body of the C regions of the alpha, beta and the related gamma polypeptide chains were "engineered" into the intronic region between the rearranged Ig variable (V) region and C kappa region genes. All three chimeric genes were expressed in myeloma cells, and the proteins of expected apparent molecular weight were produced. Secreted proteins containing the C beta domain were purified from the culture supernatant by using anti-kappa antibody affinity columns, and two rabbits were then immunized with the purified protein. Both rabbits produced antibodies able to immunoprecipitate the heterodimeric TCR protein.
...
PMID:A novel approach for preparing anti-T cell receptor constant region antibodies. 308 59

The human T cell antigen-receptor gamma chain, which is expressed on the surface of a subpopulation of CD3+ T lymphocytes, exhibits size polymorphism and varies in its ability to form disulfide bonds with a second polypeptide. Analysis of both genomic and complementary DNA clones encoding the human gamma polypeptide shows differences in lengths of the coding portions of the two constant region genes, C gamma 1 and C gamma 2. A single second-exon segment is always present in the C gamma 1 gene. C gamma 2 alleles containing either duplicated or triplicated second-exon segments are present in the normal human population and are expressed as messenger RNAs. Furthermore, a cysteine residue, encoded by the second exon of C gamma 1 and probably involved in interchain disulfide bridging, is absent in all C gamma 2 second-exon segments. These differences between C gamma 1 and the two alleles of C gamma 2 may explain the variability in molecular weight and disulfide bonding of gamma molecules expressed in different cells.
...
PMID:Molecular diversity of the human T-gamma constant region genes. 311 43

1 2 Next >>