Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biosynthesis of a secretory protein and a transmembrane viral glycoprotein are compared by two different experimental approaches. (a) NH2-terminal sequence analysis has been performed on various forms of the transmembrane glycoprotein of vesicular stomatitis virus synthesized in cell-free systems. The sequence data presented demonstrate that the nascent precursor of the glycoprotein contains a "signal sequence" of 16 amino acids at the NH2 terminus, whose sequence is Met-Lys-Cys-Leu-Leu-Tyr-Leu-Ala-Phe-Leu-Phe-Ile-(His-Val-Asn)-Cys. This signal sequence is proteolytically cleaved during the process of insertion into microsomal membranes prior to chain completion. The new NH2 terminus of the inserted, cleaved, and glycosylated membrane protein is located within the lumen of the microsomal vesicles and is identical to that of the authentic glycoprotein from virions. (b) Nascent chain competition experiments were performed between this glycoprotein, bovine pituitary prolactin (a secretory protein), and rabbit globin (a cytosolic protein). It was found that the nascent membrane glycoprotein, but not nascent globin, competed with nascent prolactin for membrane sites involved in the early biosynthetic event of transfer across membranes. These data suggest that an initially common pathway is involved in the biogenesis of secretory proteins and at least one class of integral membrane proteins.
 ...
PMID:A signal sequence for the insertion of a transmembrane glycoprotein. Similarities to the signals of secretory proteins in primary structure and function. 21 27

The purpose of these experiments was to study the physical structure of the nucleocapsid-M protein complex of vesicular stomatitis virus by analysis of nucleocapsid binding by wild-type and mutant M proteins and by limited proteolysis. We used the temperature-sensitive M protein mutant tsO23 and six temperature-stable revertants of tsO23 to test the effect of sequence changes on M protein binding to the nucleocapsid as a function of NaCl concentration. The results showed that M proteins from wild-type, mutant, and three of the revertant viruses had similar NaCl titration curves, while the curve for M proteins from the other three revertants differed significantly. The altered NaCl dependence of M protein was correlated with a single amino acid substitution from Phe to Leu at position 111 compared with the original temperature-sensitive mutant and was not correlated with a substitution of Gly to Glu at position 21 in tsO23 and the revertants. To determine whether protease cleavage sites in the M protein were protected by interaction with the nucleocapsid, nucleocapsid-M protein complexes were subjected to limited proteolysis with trypsin, chymotrypsin, or Staphylococcus aureus V8 protease. The initial trypsin and chymotrypsin cleavage sites, located after amino acids 19 and 20, respectively, were as accessible to proteases when M protein was bound to the nucleocapsid as when it was purified, indicating that this region of the protein does not interact directly with the nucleocapsid. Furthermore, trypsin or chymotrypsin treatment released the M protein fragments from the nucleocapsid, presumably due to conformational changes following proteolysis. V8 protease cleaved the M protein at position 34 or 50, producing two distinct fragments. The M protein fragment produced by V8 protease cleavage at position 34 remained associated with the nucleocapsid, while the fragment produced by cleavage at position 50 was released from the nucleocapsid. These results suggest that the amino-terminal region of the M protein around amino acid 20 does not interact directly with the nucleocapsid and that conformational changes resulting from single-amino-acid substitutions at other sites in the M protein are important for this interaction.
 ...
PMID:Sequences of the vesicular stomatitis virus matrix protein involved in binding to nucleocapsids. 184 35

Full-length cDNA copies of mRNAs coding for the matrix (M) proteins of vesicular stomatitis virus and its mutant tsO23(III) were cloned in pBSM13- (BlueScribe). The authenticity of these clones was demonstrated by restriction enzyme mapping, DNA sequencing, and in vitro transcription and translation to identify the two M proteins by Western immunoblotting with epitope-specific monoclonal antibodies. Site-directed mutants were constructed by primer extension of synthetic oligodeoxynucleotides with one or two nucleotide changes to alter the glycine at amino acid 21 of the wild-type (wt) M gene to glutamic acid, alanine, or proline. Similarly, a revertant was created in the M gene of mutant tsO23 by a Glu-21----Gly substitution. A series of wt- and mutant-M-gene chimeras was also constructed to create mutant and revertant clones with Leu----Phe and His----Tyr alterations at amino acids 111 and 227, respectively. We then moved the wt and tsO23 M genes and their site-specific mutants and chimeras cloned in pBSM13- into the eucaryotic expression vector pTF7 directed by the T7 bacteriophage RNA polymerase of the vaccinia virus recombinant vTF1-6,2. Western blot analysis of the M proteins transiently expressed in CV-1 cells by plasmids carrying M genes altered at amino acid 21 revealed that the critical antigenic determinant (epitope 1) is expressed only by the Gly-21 M protein and not by Glu-21, Ala-21, or Pro-21 M proteins. Of particular interest is an apparent conformational change, evidenced by slightly but significantly retarded electrophoretic migration, in plasmid-expressed M proteins with amino acids substituted for glycine at position 21. The glutamic acid at position 21 of tsO23 is not responsible for its temperature-sensitive phenotype, because a tsO23 revertant plasmid with glycine substituted at position 21 fails to rescue tsO23 virus in cells infected at the restrictive temperature; conversely, plasmids expressing wt M protein with substitutions of glutamic acid, alanine, or proline at position 21 are just as effective in marker rescue of tsO23 as is the Gly-21 wt M protein. Marker rescue experiments with wt- and mutant-M-gene chimeras support the hypothesis of K. Morita, R. Vanderoef, and J. Lenard (J. Virol. 61:256-263, 1987) that the temperature-sensitive phenotype of tsO23 is due to a phenylalanine substituted for leucine at amino acid 111, rather than the His-227----Tyr substitution or the Gly-21----Glu substitution, which independently accounts for the loss of epitope 1 in the mutant M protein of tsO23.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Site-specific mutations in vectors that express antigenic and temperature-sensitive phenotypes of the M gene of vesicular stomatitis virus. 245 88

The matrix (M) protein of vesicular stomatitis virus serves as an endogenous inhibitor of viral transcription, a function missing or deficient in M proteins of temperature-sensitive (ts) mutants assigned to complementation group III. Previous studies with mutant tsO23(III) and vaccinia virus M-gene expression vectors revealed that the temperature-sensitive phenotype is due to a mutation leading to substitution of phenylalanine for leucine at amino acid III, whereas loss of the major antigenic determinant (epitope 1) of the mutant M protein results from the substitution of glutamic acid for the wild-type amino acid glycine at position 21 (Y. Li, L. Luo, R. M. Snyder, and R. R. Wagner, J. Virol. 62:3729-3737, 1988). We demonstrate here that transcription inhibition activity is restored to rescued tsO23 virus only when the rescuing vaccinia virus recombinant expresses M protein with glycine and not glutamic acid at amino acid 21. These experiments indicate the importance of the conformational integrity of the amino-terminal domain in determining the capacity of the vesicular stomatitis virus M protein to down regulate endogenous transcription.
 ...
PMID:Transcription inhibition site on the M protein of vesicular stomatitis virus located by marker rescue of mutant tsO23(III) with M-gene expression vectors. 254 94

DNA sequences were determined for three cDNA clones encoding vesicular stomatitis virus glycoproteins from the tsO45 mutant (which encodes a glycoprotein that exhibits temperature-sensitive cell-surface transport), the wild-type parent strain, and a spontaneous revertant of tsO45. The DNA sequence analysis showed that as many as three amino acid changes could be responsible for the transport defect. By recombining the cDNA clones in vitro and expressing the recombinants in COS cells, we were able to trace the critical lesion in tsO45 to a single substitution of a polar amino acid (serine) for a hydrophobic amino acid (phenylalanine) in a hydrophobic domain. We suggest that this nonconservative substitution may block protein transport by causing protein denaturation at the nonpermissive temperature. Comparison of the predicted glycoprotein sequences from two vesicular stomatitis virus strains suggests a possible basis for the differential carbohydrate requirement in transport of the two glycoproteins.
 ...
PMID:A single amino acid substitution in a hydrophobic domain causes temperature-sensitive cell-surface transport of a mutant viral glycoprotein. 298 3

The conformations of synthetic peptides Lys-Phe-Phe-Phe-Ile-Ile-Gly-Leu-Ile-Ile-Gly-Leu-Phe-OCH3 and Lys(epsilon-palmitoyl)-Phe-Phe-Phe-Ile-Ile-Gly-Leu-Ile-Ile-Gly-Leu-Phe-O CH3, which constitute a part of the membrane-spanning region of the vesicular stomatitis virus G protein, have been studied by circular dichroism (CD) spectroscopy. Secondary structural features are observed for both peptides in trifluoroethanol, methanol, aqueous mixtures of trifluoroethanol and methanol and in a micellar environment. In trifluoroethanol, the CD spectra indicate the presence of a helical conformation, whereas in aqueous mixtures of organic solvents, both helical and beta-conformations are observed. While fatty acid acylation does not directly modulate peptide conformation, it promotes self-association of the acylated peptide and association with micelles. In a micellar environment, the acylated peptide adopts an alpha-helical conformation.
 ...
PMID:Circular dichroism studies on a synthetic peptide corresponding to the membrane-spanning region of vesicular stomatitis virus G protein and its fatty acyl derivative. 302 85

Polymorphonuclear leukocyte (PMN) function was investigated in two patients with glycogen storage disease type IB and neutropenia. Glycogen storage disease type IB was documented by liver biopsy and a normal amount of latent glucose-6-phosphatase activity. Patient A had stomatitis, skin infections, and septicemia; patient B had respiratory infections, periodontitis, and oral candidiasis. Absolute neutrophil counts ranged from 114 to 2580/mm3. Diminished and delayed migration of PMN into a skin "window" occurred in B. Random and directed PMN migration under agarose toward f-Met-Leu-Phe, pepstatin A, and zymosan-activated serum were severely diminished in both patients. At 10(-7) M f-Met-Leu-Phe, mean random and directed migration were 52 and 23% (A, n = 3) and 48 and 13% (B, n = 4) of controls. These results were independent of incubation time and chemoattractant concentration. Patients' PMN had diminished quantitative nitroblue tetrazolium reduction compared to controls. B had a significant defect in PMN bactericidal activity with Escherichia coli with less than 0.2 log killing at 2 h. These results further characterize the defect in PMN migration reported by Beaudet et al. (J Pediatr 97:906, 1980). The finding of other abnormalities of PMN function suggests a metabolic defect in the neutrophil which may be related to the microsomal membrane defect in hepatocytes in glycogen storage disease type IB.
 ...
PMID:Impaired chemotaxis and neutrophil (polymorphonuclear leukocyte) function in glycogenosis type IB. 345 31

Our long-term goal is to define the catalytic domains of the L protein subunit of the Sendai virus RNA polymerase. An aberrant polyadenylation phenotype in the vesicular stomatitis virus tsG16 L protein mutant has recently been identified as a phenylalanine to serine change at amino acid 1488 (Hunt and Hutchinson, Virology 193, 786-793, 1993). To test if functional domains are conserved in the L proteins of negative-strand RNA viruses, we attempted to create a similar polyadenylation defect in the Sendai virus L protein. Nine different amino acid substitutions at the analogous site in the Sendai L protein (cysteine at amino acid 1571) were constructed by site-directed mutagenesis of the gene. Each mutant L protein was synthesized and bound to the Sendai P protein to form the P-L polymerase complex. While none of these L mutants exhibited a change in polyadenylation, the single amino acid changes yielded a variety of activities in vitro. Mutants containing valine, leucine, or phenylalanine at amino acid 1571, amino acids found naturally in the L proteins of other paramyxoviruses, yielded polymerases that had biological activity equal to or better than the wild-type (WT) polymerase. Serine or threonine substitutions in the L protein at this position also resulted in polymerases with nearly WT synthetic activity. In contrast, a glycine substitution significantly decreased overall polymerase activity, whereas a tyrosine substitution gave decreased transcription, but virtually no DI genome replication in vitro. The tyrosine-substituted polymerase may be unable to carry out the packaging step of replication, since DI leader RNA synthesis was normal in this mutant. Mutant L proteins with basic arginine or histidine substitutions were inactive in all viral RNA synthesis in vitro, although the polymerase complexes could bind the nucleocapsid template.
 ...
PMID:Alternative amino acids at a single site in the Sendai virus L protein produce multiple defects in RNA synthesis in vitro. 764 61

Transfection of mammalian CV1 cells with a recombinant M-gene pTM1 plasmid, driven by vaccinia virus-expressed phage T7 polymerase, resulted in the expression of matrix (M) protein, which is progressively released from the exterior surface of the transfected-cell plasma membrane. Exocytosis of M protein begins 2 to 4 h posttransfection and reaches a peak by 10 to 16 h posttransfection; dye uptake studies reveal that > 97% of cells are alive and have intact membranes at 16 h posttransfection. Density gradient centrifugation and labeling with radioactive palmitic acid revealed that the M protein is released from cells in association with lipid vesicles. Expression of M-gene deletion mutants suggests that exocytosis of M protein requires the presence of a membrane-binding site at N-terminal amino acids 1 to 50. Cells transfected with the pTM1 plasmid containing the M gene of the temperature-sensitive mutant tsO23 expressed ample quantities of the mutant M protein at permissive (31 degrees C) and restrictive (39 degrees C) temperatures, but the exocytosis of the mutant M protein occurred only at the permissive temperature. The tsO23 M gene has three site-specific mutations resulting in amino acid substitutions at residues 21, 111, and 227. Expression of wild-type and mutant M genes with mutations or revertants at each of these sites resulted in exocytosis of M protein at the nonpermissive temperature only when wild-type leucine was present at residue 111, but M-protein exocytosis was restricted (to some extent even at the permissive temperature) when mutant phenylalanine was present at residue 111. Past and present data indicate that a specific structural conformation of the M protein is responsible for the formation and budding of vesicles, a property of the M protein which probably also promotes vesicular stomatitis virus assembly and budding of virions from host cells.
 ...
PMID:Membrane vesiculation function and exocytosis of wild-type and mutant matrix proteins of vesicular stomatitis virus. 770 43

Investigations in newborns, children and young adults have revealed an inverse proportion between aminoaciduria and plasma hemoglobin (Hb) levels. Values above normal were recorded for alanine, leucine, valine, phenylalanine and glutamic acid, correlating proportionally with their increased blood levels, and preceding or being concomitant with the decrease of plasma Hb, both during the first 20 months of life and in young adults. The return to near normal values of aminoaciduria occurred generally only after an early treatment with minerals, vitamins and trace elements (Supradyn), activators of the enzymes involved in the amino acid metabolism. After treatment, the Hb levels also became almost normal. An early re-equilibration of the amino acid metabolism can prevent the risk of developing, at the adult age, certain anemias and other diseases (rachitism, mental handicap, urinary infections, conjunctivitis, stomatitis, a.o.). The correlation factor was r = 0.964 and the differences between the data recorded in patients and in controls were statistically significant (p < 0.01).
 ...
PMID:The relationship between aminoaciduria and plasma hemoglobin levels. 813 Jul 61


1 2 3 Next >>