Sequential transcription of the genes of vesicular stomatitis virus

Increasing exposure of vesicular stomatitis virus particles to ultraviolet radiation caused differential inhibition of the synthesis in vitro of individual mRNA species which code for the viral structural proteins L, G, M, NS, and N.

Improving cancer radiotherapy with 2-deoxy-D-glucose: phase I/II clinical trials on human cerebral gliomas

PURPOSE

Evaluation of tolerance, toxicity, and feasibility of combining large fraction (5 Gy) radiotherapy with 2-deoxy-D-glucose (2DG), an inhibitor of glucose transport and glycolysis, which has been shown to differentially inhibit repair of radiation damage in cancer cells.

METHODS AND MATERIALS

Twenty patients with supratentorial glioma (Grade 3/4), following surgery were treated with four weekly fractions of oral 2DG (200 mg/kg body weight) followed by whole brain irradiation (5 Gy). Two weeks later, supplement focal radiation to the tumor (14 Gy/7 fractions) was given. Routine clinical evaluation, x-ray computerized tomography (CT), and magnetic resonance (MR) imaging were carried out to study the acute and late radiation effects.

RESULTS

All the 20 patients completed the treatment without any interruption. The vital parameters were within normal limits during the treatment. None reported headache during the treatment. Mild to moderate nausea and vomiting were observed during the days of combined therapy (2DG + RT) in 10 patients. No significant deterioration of the neurological status was observed during the treatment period. Seven patients were alive at 63, 43, 36, 28, 27, 19, and 18 months of follow-up. In these patients, the clinical and MR imaging studies did not reveal any late radiation effects.

CONCLUSIONS

Feasibility of administering the treatment (2DG + 5 Gy) is demonstrated by the excellent tolerance observed in all 20 patients. Further, the clinical and MR studies also show the absence of any brain parenchymal damage.

Methylation-dependent translation of viral messenger RNAs in vitro

Methylated reovirus and vesicular stomatitis virus mRNAs, synthesized in vitro in the presence of S-adenosylmethionine by the virion-associated polymerases (RNA nucleotidyltransferases, EC 2.7.7.6), stimulate protein synthesis by wehat germ extracts to a greater extent than unmethylated mRNAs. Addition of S-adenosylmethionine to a cell-free extract programmed with unmethylated mRNA stimulates protein synthesis and results in methylation of the mRNA. An inhibitor of mRNA methylation. S-adenosylhomocysteine, blocks translation of unmethylated, but not of methylated, mRNAs. Aurintricarboxylic acid, which inhibits polypepetide chain initiation, also prevents mRNA methylation by wheat germ extracts. In contrast, sparsomycin, which inhibits polypeptide chain elongation, does not reduce mRNA methylation. The results indicate that methylation of viral mRNA is required for translation in vitro and suggest that mRNA methylation occurs at the initiation step of protein synthesis.

The 5' terminal structure of the methylated mRNA synthesized in vitro by vesicular stomatitis virus

The 5' terminal structure of the mRNA synthesized in vitro by the virion-associated RNA polymerase of vesicular stomatitis virus in the presence of S-adenosyl-L-methione consists of 7-methyl guanosine linked to 2'-O-methyl adenosine through a 5'-5' pyrophosphate bond as m7G(5')ppp(5')A-m-p ... The alpha and beta phosphated of GTP and alpha phosphate of ATP are incorporated into the blocked 5' terminal structure.

Patterns of urine flow and electrolyte excretion in healthy elderly people

Twenty four young (mean age 29.2 years, range 25-35) and 21 elderly (mean age 66.5, range 60-80) healthy subjects collected their urine in timed aliquots over 24 hours. The elderly subjects had been selected for their fitness by clinical and laboratory examinations and all lived independently at home. Sodium and potassium excretions were reduced in the elderly subjects compared with the young subjects, potassium excretion considerably so. This was despite similar 24 hour urine volumes and total solute excretion by both groups. The ratios of rates of excretion of water, electrolytes, and solutes during the night to the rates of excretion during the day were found to be higher in the elderly than the young subjects. Reduced day to night ratios of urinary excretion may be partly responsible for complaints of nocturia and sleep disturbance in elderly people.

A unique RNA species involved in initiation of vesicular stomatitis virus RNA transcription in vitro

Purified virions of vesicular stomatitis virus (VSV) are capable of synthesizing two distinct types of virus-specific RNA in vitro. The first consists of several viral mRNAs which have been previously shown to contain the blocked 5' terminal sequence GpppApApCpApGp and 3' terminal poly(A). The second type of RNA has an unblocked 5' terminus and does not contain poly(A) stretches long enough to bind to oligo (dT)-cellulose columns. It migrates in 20% polyacrylamide gels as a single homogeneous peak with an estimated chain length of 68 nucleotides. Base analysis demonstrated that this small RNA molecule is composed of 48% AMP, 20% CMP, 11% GMP, and 21% UMP. The 5' terminal sequence of the small RNA is ppApCpGp, which appears to be complementary to the 3' terminal sequence of the VSV genome RNA (...PypGpU). These results indicate that this small RNA molecule probably represents the intitiated lead-in RNA segment which is removed during formation of VSV mRNAs by a possible processing mechanism.

Common variable immune deficiency: respiratory manifestations, pulmonary function and high-resolution CT scan findings

BACKGROUND

Common variable immune deficiency (CVID) is prone to under-diagnosis and may not reach relevant specialists until late in life. Morbidity is most commonly due to acute-on-chronic respiratory infections leading to respiratory failure.

AIM

To investigate respiratory complications, lung function and high-resolution computerized tomography scan (HRCT) findings and mortality in 47 patients with CVID.

SETTING

A regional immunology unit (Birmingham Heartlands Hospital).

DESIGN

Retrospective observational case-note study following the introduction of shared care between immunology and respiratory medicine.

RESULTS

Age at diagnosis ranged from 5 to 72 years, with a median time from development of first symptoms to diagnosis of 4.0 years. There was delay in referral between chest physicians and immunologists, (median referral time between specialities >5 years). Forty-two patients had respiratory complications, due to bronchiectasis (n=32), asthma (n=7), recurrent chest infections (n=9) without concomitant evidence of structural lung damage, and granulomatous lung disease (n=2). Spirometry was abnormal in 10/39 patients (7 obstructive, 3 restrictive). Bronchiectasis was confirmed on chest radiograph (n=9) and HRCT (n=24). Despite the high prevalence of bronchiectasis, few patients had received instruction in physiotherapy and sputum culture results were sparse.

DISCUSSION

To reduce the morbidity associated with CVID, there needs to be greater awareness of respiratory complications, particularly amongst physicians caring for such patients. Emphasis has been placed on adequate dosage of immunoglobulin, but early involvement by a respiratory physician is essential to monitor lung function and initiate optimal therapy, to minimize the occurrence and progression of lung damage.

11beta-hydroxysteroid dehydrogenase type 1 activity in lean and obese males with type 2 diabetes mellitus

Glucocorticoids play an important role in the pathogenesis of obesity and insulin resistance. Impaired conversion of cortisone (E) to cortisol (F) by the type 1 isoenzyme of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) in obesity may represent a protective mechanism preventing ongoing weight gain and glucose intolerance. We have studied glucocorticoid metabolism in 33 male subjects with type 2 diabetes mellitus [age, 44.2 +/- 13 yr; body mass index (BMI), 31.1 +/- 7.5 kg/m(2) (mean +/- sd)] and 38 normal controls (age, 41.4 +/- 14 yr; BMI, 38.2 +/- 12.8 kg/m(2)). Circulating F:E ratios were elevated in the diabetic group and correlated with serum cholesterol and homeostasis model assessment-S. There was no difference in 11beta-HSD1 activity between diabetic subjects and controls. In addition, 11beta-HSD1 activity was unaffected by BMI in diabetic subjects. However, in control subjects, increasing BMI was associated with a reduction in the urinary tetrahydrocortisol+5alpha-tetrahydrocortisol:tetrahydrocortisone ratio (P < 0.05) indicative of impaired 11beta-HSD1 activity. The degree of inhibition correlated tightly with visceral fat mass. Changes in 11beta-HSD1 activity could not be explained by circulating levels of adipocytokines. Impaired E to F metabolism in obesity may help preserve insulin sensitivity and prevent diabetes mellitus. Failure to down-regulate 11beta-HSD1 activity in patients with diabetes may potentiate dyslipidemia, insulin resistance, and obesity. Inhibition of 11beta-HSD1 may therefore represent a therapeutic strategy in patients with type 2 diabetes mellitus and obesity.

Complex formation with vesicular stomatitis virus phosphoprotein NS prevents binding of nucleocapsid protein N to nonspecific RNA

The interactions between the nucleocapsid protein N and either RNA or the phosphoprotein NS of vesicular stomatitis virus (VSV) were studied by the transcription of N and NS mRNAs from SP6 vectors, followed by translation in a rabbit reticulocyte lysate. Nascent N protein bound tightly to added labeled RNA, as well as to endogenous RNA in the reticulocyte lysate. This binding was demonstrated by three independent techniques. First, labeled N protein and labeled RNA migrated identically as a series of sharp, closely spaced bands in a nondenaturing gel system. Second, translated N protein behaved as a stable ribonucleoprotein complex in CsCl gradients and sedimented to the same density as the authentic N-RNA template of VSV. Third, translated N protein protected a series of labeled RNA fragments from digestion by RNase A. None of the three RNA-binding criteria was satisfied by either translated NS protein or two deletion mutants of N protein or by other components of the reticulocyte lysate. The evidence suggests that the observed binding of RNA by nascent N was not RNA sequence specific, in contrast to the encapsidation process during VSV replication. Moreover, the prior formation of N-NS complexes totally abolished the observed binding of RNA by N. Thus, we propose that NS may be responsible for conferring the sequence specificity of the RNA binding that occurs during VSV genome replication.

Endoscopic transthoracic sympathectomy in the treatment of hyperhidrosis

A 5-year experience of 50 endoscopic transaxillary dorsal sympathectomies is presented. The procedure was successful in either curing or improving the symptoms of hyperhidrosis in the great majority of patients. The commonest side effects were compensatory sweating (75%) and gustatory sweating (48%); despite this, there was an extremely high level of patient satisfaction. Permanent Horner's syndrome did not occur. The procedure is effective, simple, cheap, and requires only an overnight stay; and is recommended as the method of choice for the surgical treatment of upper limb hyperhidrosis.

Phosphorylation by cellular casein kinase II is essential for transcriptional activity of vesicular stomatitis virus phosphoprotein P

We have previously shown that phosphorylation of vesicular stomatitis virus (VSV) phosphoprotein P by cellular protein kinase activity is an essential prerequisite for its transcriptional function. We have now purified this protein kinase by monitoring its ability to phosphorylate bacterially expressed, unphosphorylated P protein. Biochemical studies showed that the kinase is indistinguishable from casein kinase II, a ubiquitous cyclic AMP-independent protein kinase present in a wide variety of eukaryotic cells and tissues. Functional VSV transcription could be reconstituted with viral L protein, N-RNA template, and P protein phosphorylated by either purified cellular protein kinase or purified casein kinase II. The unusual role of casein kinase II in the transcription process of a nonsegmented negative-strand RNA virus would have important implications in host-virus interactions and antiviral therapy.

Transcriptional activity and mutational analysis of recombinant vesicular stomatitis virus RNA polymerase

The 241-kDa large (L) protein of vesicular stomatitis virus (VSV) is the multifunctional catalytic component of the viral RNA polymerase. A protocol has been developed for the synthesis of recombinant L protein that will support viral mRNA synthesis in vitro. COS cells were transfected with a transient expression vector (pSV-VSL1 [M. Schubert, G. G. Harmison, C. D. Richardson, and E. Meier, Proc. Natl. Acad. Sci. USA 82:7984-7988, 1985]) which contains the simian virus 40 late promoter for the transcription of a cDNA copy of the L protein of the Indiana serotype of VSV. Cytoplasmic extracts of these cells efficiently transcribed VSV mRNAs in vitro in conjunction with N protein-RNA template purified from virus and recombinant phosphoprotein synthesized in Escherichia coli. mRNA synthesis was completely dependent upon addition of both bacterial phosphoprotein and extracts from cells transfected with the L gene. Extracts from mock-transfected cells or from cells transfected with the expression vector alone did not support VSV RNA synthesis. RNA synthesis was proportional to the concentration of cell extract used, with an optimum of 0.2 mg/ml. Rhabdoviruses and paramyxoviruses contain a highly conserved GDNQ motif which was mutated in the transfected L gene. All constructs with mutations within the core GDN abrogated transcriptional activity except for the mutant containing GDD, which retained 25% activity. Conserved amino acid changes outside of the core GDN and changes corresponding to other paromyxovirus and rhabdovirus L proteins retained variable transcriptional activity. These findings provide experimental evidence that the GDN of negative-strand, nonsegmented RNA viruses is a variant of the GDD motif of plus-strand RNA viruses and of the XDD motif of DNA viruses and reverse transcriptases.

Influence of 5'-terminal m7G and 2'--O-methylated residues on messenger ribonucleic acid binding to ribosomes

Removal of 80% of the 5'-terminal 7-methyl-guanosine (m7G) from methylated reovirus mRNA by beta elimination results in a concomitant loss of the ability to bind to wheat germ ribosomes. The mRNA molecules that retain the m7G account for most of the residual binding. Removal of the m7G from all molecules in preparations of methylated reovirus and vesicular stomatitis virus mRNA reduces the extent of binding to wheat germ ribosomes from 80% to 5-7%. In the reticulocyte lysate, however, significant binding (17-34%) of the beta-eliminated viral RNAs occurs. This m7G-independent binding appears to be due to recognition by ribosomes of other structural features of the 5'-proximal sequences. Initiation complexes involving beta-eliminated animal virus mRNAs and rabbit reticulocyte ribosomes appear to be more stable than the more heterologous combination of the same viral mRNAs and wheat germ ribosomes. In addition, evidence is presented to show that the 2'-O-methylated nucleoside of the 5'-terminal cap has a positive influence on the ribosome binding of viral mRNA and of capped synthetic ribopolymers. A model involving recognition of multiple structural features of the 5'-terminal region of mRNA by ribosomes during initiation of protein synthesis is presented.

Specific interaction in vitro and in vivo of glyceraldehyde-3-phosphate dehydrogenase and LA protein with cis-acting RNAs of human parainfluenza virus type 3

Human parainfluenza virus type 3 (HPIV3) genome RNA is transcribed and replicated by the virus-encoded RNA-dependent RNA polymerase, and specific cellular proteins play a regulatory role in these processes. To search for cellular proteins potentially interacting with HPIV3 cis-acting regulatory RNAs, a gel mobility shift assay was used. Two cellular proteins specifically interacted with the viral cis-acting RNAs containing the genomic 3'-noncoding region and the plus-sense leader sequence region. Surprisingly, by biochemical and immunological analyses, one of the cellular proteins was identified as the key glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The other protein was characterized as the autoantigen, LA protein. Both GAPDH and LA protein also interacted with the same cis-acting RNA sequences in vivo and were found to be associated with the HPIV3 ribonucleoprotein complex in the infected cells. By double immunofluorescent labeling, GAPDH was found to be co-localized with viral ribonucleoprotein in the perinuclear region. These observations strongly suggest that cellular GAPDH and LA Protein participate in the regulation of HPIV3 gene expression.

Complete nucleotide sequence of the leader RNA synthesized in vitro by vesicular stomatitis virus

The complete nucleotide sequence of the leader RNA synthesized in vitro by the Indiana serotype of vesicular stomatitis virus is presented. The sequence was determined by the technique described by Donis-Keller, Maxam and Gilbert (1977) in combination with the standard two-dimensional fingerprint techniques described by Barrell (1971). The leader RNA contains 48 nucleotides variably terminating at the 3' terminus with cytosine (68%) and adenosine at position 47 (32%). Since the leader RNA is complementary to the 3' terminal portion of the viral genome RNA, the first 48 nucleotides from the 3' end of the genome RNA can be decuded. The leader RNA contains repetitive and palindromic sequences with a polypurine sequence at its 3' terminus. The possible role of some of the sequences is discussed.

Unique mode of transcription in vitro by Vesicular stomatitis virus

In addition to the five mRNA species and 47 nucleotide long leader RNA synthesized by purified virions of vesicular stomatitis virus, at least three discrete low molecular weight RNA species having approximate chain lengths of 28, 42 and 70 nucleotides can be detected in vitro. Each of these RNA species displays a unique and characteristic T1 fingerprint profile and contains (p)ppAA as its 5' terminus. By partial sequence analyses, two of the small RNA products, 42 and 28 bases long, were found to contain 5' terminal sequences identical to those in the N and NS mRNAs, respectively. Ultraviolet inactivation studies demonstrate that each of these RNA species has a target size in agreement with its molecular weight indicating independent initiation. Kinetic studies show that the small RNA species are synthesized within 1 min, while mRNA chain completion occurs later in the sequential order N-NS-M-G. These results indicate that viral mRNA synthesis occurs in vitro by multiple initiations at different promoter sites on the genome RNA, and that the elongation and completion of the individual mRNAs depend on prior transcription of 3' proximal genes. We present a model for viral mRNA synthesis in vitro.

Transcription in vitro by reovirus-associated ribonucleic acid-dependent polymerase

Digestion of purified reovirus type 3 with chymotrypsin degrades 70% of the viral protein and converts the virions to subviral particles (SVP). The SVP contain 3 of the 6 viral structural proteins and all 10 double-stranded ribonucleic acid (RNA) genome segments but not adenine-rich, single-stranded RNA. An RNA polymerase which is structurally associated with SVP transcribes one strand of each genome segment by a conservative mechanism in vitro. The single-stranded products include large (1.2 x 10(6) daltons), medium (0.7 x 10(6) daltons), and small (0.4 x 10(6) daltons) molecules which hybridize exclusively with the corresponding genome segments. The enzyme obtained by heating virions at 60 C synthesizes similar products. Kinetic and pulse-chase studies indicate that the different-sized products are synthesized simultaneously but at rates which are in the order: small > medium > large.

Methylated and blocked 5' termini in vesicular stomatitis virus in vivo mRNAs

Methyl groups derived from 3H-methyl methionine were incorporated into vesicular stomatitis virus (VSV) MRNAs isolated from infected cells. Sequential degradation of the 12-18S viral mRNA species with ribonuclease T2, penicillium nuclease, and alkaline phosphatase yielded a single 3H-labeled dinucleotide. A similar resistant 32P-labeled fragment was obtained by digesting VSV mRNA uniformly labeled with 32P. This methylated and blocked oligomer was further cleaved with nucleotide pyrophosphatase, yielding two methylated 5' nucleotides. We postulate that the 5' terminal structure of the vivo 12-18S VSV mRNA contains 7-methylguanosine linked by a 5'-5' pyrophosphate bond to a methylated derivative of adenosine. In contrast to the mRNAs (+ strand), the VSV genome RNA ( MINUS STRAND) IS NOT BLOCKED.

Sequential phosphorylation of the phosphoprotein of vesicular stomatitis virus by cellular and viral protein kinases is essential for transcription activation

The phosphoprotein (P) and the large protein (L) constitute the RNA-dependent RNA polymerase of vesicular stomatitis virus (VSV). We show that phosphate-free P protein expressed in bacteria is transcriptionally inactive when reconstituted with L protein and viral N-RNA template free of cellular protein kinase. Phosphorylation of P protein by a cellular kinase(s) was essential for transcription as well as for further phosphorylation by an L-associated kinase, the two kinases acting in a sequential (cascade) manner. Phosphate groups introduced by cell kinase were stable, whereas those due to L kinase underwent a turnover which was coupled to ongoing transcription. We present a model for the phosphorylation pathway of P protein and propose that continued phosphorylation and dephosphorylation of P protein may represent a transcriptional regulatory (on-off) switch of nonsegmented negative-strand RNA viruses.

Association of simple anthropometric measures of obesity with visceral fat and the metabolic syndrome in male Caucasian and Indo-Asian subjects

AIMS

The aims of this study were first, to investigate the relationship between simple anthropometric measures of obesity with visceral fat as assessed by a single slice magnetic resonance imaging (MRI)-scan in patients attending a hospital clinic. Second, to determine which anthropometric measure best relates to the adverse metabolic profile of the metabolic syndrome.

METHODS

Forty-one male subjects [body mass index (BMI): 30.2 + 5.8 kg/m(2), age: 50.3 + 13.6 years] were studied by MRI-scan to measure visceral fat at L4/L5 level and to investigate its relationship with simple anthropometric measures. Second, we studied 83 male subjects to determine which anthropometric measure best predicts the metabolic complications (using the ATPIII criteria) of obesity in the setting of a hospital clinic.

RESULTS

Waist circumference was the best anthropometric measurement that correlated with MRI-visceral fat mass assessed at L4/L5 in 41 subjects who had an MRI scan (P = 0.0001, r(2) = 0.36, beta = 0.56) amongst variables which also included age, BMI, sagittal diameter, diabetes and ethnicity. Stepwise multiple regression analysis showed sagittal diameter (P = 0.001, r(2) = 0.4, beta = 0.406), age (P = 0.003, beta = 0.271) and waist circumference (P = 0.012, beta = 0.297) were the best predictors of the adverse metabolic profile of the metabolic syndrome in all 83 male subjects amongst BMI, waist-hip ratio (WHR), ethnicity and diabetes-related factors.

CONCLUSIONS

Waist circumference is a simple anthropometric parameter that best correlates with single slice MRI-scan, but sagittal diameter (measured using abdominal calipers) better predicts the adverse metabolic profile of the metabolic syndrome. Although there is considerable variation in abdominal fat topography between ethnic groups, and also within populations, sagittal diameter assessment is a technique that is simple and best predicts the metabolic syndrome.