Copper in various phases of several olivine-hypersthene and olivine-bronzite chondrites

Determinations of Cu in separate phases of three olivine-hypersthene and one olivine-bronzite chondrites show that it is very strongly concentrated in the taenite; appreciable amounts are present in the olivine, less in the pyroxene plus plagioclase; it is probable that the copper found in the ‘unattracted, attacked’ fraction is present as metallic copper, and that very little is present in the sulphides.

Methods for the chemical analysis of meteorites: II. The major and some minor constituents of chondrites

Pure dry chlorine at 250 to 350° C is shown to have no action on the principal silicate and phosphate phases of meteorites, but reacts quantitatively with the sulphide and phosphide phases and with kamacite; taenite does not react if it contains more than about 20 to 25 % Ni; some rare meteoritic minerals have not yet been tested. Volatile chlorides (including SiCl4) distil, and non-volatile chlorides can be leached out with water. Based on these observations, a method has been devised and applied to the analysis of a number of chondrites and to the purification of olivine and pyroxene separated by physical methods. The amount of Si present in the metal of enstatite chondrites, and the distribution of P, Ga, Ge, Ti, Cr, Mn, Ca, and Mg between oxidized and non-oxidized phases can readily be determined, and some results are presented. From the limited data so far available, Co appears to be concentrated in kamacite; gallium in the metallic phase is mainly in the taenite; germanium is strongly siderophile in the common chondrites but some is present in the silicate of the enstatite chondrites; titanium is markedly chalcophile in the enstatite chondrites, less so in the common chondrites, and the same applies to chromium; phosphorus is present as phosphide in the enstatite chondrites, but as phosphate in the hypersthene chondrites.

The analysis of molybdates and tungstates

The estimation of molybdenum and tungsten when present together has proved difficult, as is indicated by the large number of methods put forward for their determination. Many of the methods given are for one or other of these elements only, a note often being added that the presence of the other invalidates the method. The estimation of molybdate and tungstate in the mineral powellite has been briefly described by one of the authors (A. A. M.): molybdate and tungstate were precipitated as oxinates (Mo,W)O2(C9H6ON)2 and the molybdate (MoO4″) determined by measurement of the optical density at 230 mµ of a solution containing molybdate and tungstate. The amount of tungstate present was then estimated by difference. The property of the molybdate ion, MoO4″, to absorb strongly in the ultra-violet has been further investigated and it has been found that, if a wave-length of 240 mµ is chosen and the proper precautions taken, the MoO4″ ion can be estimated without significant interference by the WO4″ ion. Methods are given for the analysis of the common molybdate and tungstate minerals, together with results obtained during the course of this investigation.

A cohort study of post-weaning multisystemic wasting syndrome and PCV2 in 178 pigs from birth to 14 weeks on a single farm in England

Our hypothesis was that pigs that develop post-weaning multisystemic wasting syndrome (PMWS) are detectable from an early age with signs of weight loss and other clinical and serological abnormalities. Therefore, the objective of this study was to investigate the temporally varying and fixed events linked with the clinical incidence of PMWS by comparing affected and unaffected pigs in a cohort of 178 male piglets. Piglets were enrolled at birth and examined each week. Samples of blood were collected at regular intervals. The exposures measured were porcine circovirus type 2 (PCV2) antibody titres in all 178 and PCV2 antigen in a subset of 75 piglets. We also observed piglet health and measured their weight, and a post-mortem examination was performed by an external laboratory on all pigs between 6 and 14 weeks of age that died. From the cohort, 14 (8%) pigs died from PMWS and 4% from other causes. A further 37 pigs between 6 and 14 weeks of age died from PMWS (30) and ileitis and other causes (7). PMWS was only apparent in pigs from 1 to 2 weeks before death when they wasted rapidly. There were no other characteristic clinical signs and no obvious gross clinical lesions post-mortem. There was no strong link with PCV2 antibody throughout life but PCV2 antigen level was higher from 4 to 6 weeks of age in pigs that died from PMWS compared with pigs that died from other causes.

Detection of human papillomavirus in vulval carcinoma using semi-nested PCR and restriction enzyme typing: a rapid and sensitive technique

Aims-To develop a highly sensitive technique for the reliable detection and typing of human papillomavirus (HPV) DNA in clinical tissue.Methods-A two step, semi-nested PCR was used with primers spanning the L1 region of the HPV genome and capable of detecting HPV DNA of all known HPV types. The clinical samples were typed by digestion of the 412 base pair PCR product with Rsa I, generating unique fragments for each HPV type. Thirteen samples were screened by this method, including nine vulval carcinoma samples and four wart samples from the penis and vulva.Results-Experiments using DNA extracted from HPV DNA positive cell lines-that is, CaSki (HPV type 16) and HeLa (HPV type 18) established that the technique could detect as few as 50 HPV copies and that the predicted Rsa I fragments from HPV types 16 and 18 were generated. The predicted 412 base pair fragment was observed for all 13 clinical samples subjected to semi-nested PCR. Rsa I digestion of the product of the second round of PCR permitted the positive identification of the HPV type in most cases.Conclusions-This technique provides an effective and rapid means of detecting HPV DNA, in most cases providing the HPV type. High risk HPV types were always detected in the nine vulval carcinoma samples analysed. The amount of tissue available from the biopsy specimens was small, confirming the sensitivity of the method.

Partial characterisation of five cloned viruses differing in pathogenicity, obtained from a single isolate of pigeon paramyxovirus type 1 (PPMV-1) following passage in fowls' eggs

Viruses with intracerebral pathogenicity indices (ICPIs) of 0.025, 0.55, 1.013 and 1.3. were cloned from a PPMV-1 isolate with an ICPI of 0.32 by passage in embryonated fowls' eggs. Deduced amino acid sequences of the haemagglutinin-neuraminidase (HN) and precursor fusion proteins (F0) showed them to have only a single amino acid difference: those with an ICPI value <0.7 had proline at amino acid position 453 of the F0 protein, and those with an ICPI value >0.7 contained a serine. The virus with an ICPI of 0.025 was further passaged, and the ICPI of non-cloned virus increased to 0.76/0.79, which was then reduced to 0.49 on cloning. The proline at residue 453 was retained, but there were two nucleotide changes in the virus of ICPI 0.49, T --> C at position 1769 in the untranslated region of the fusion gene and G --> A at position 437 of the HN gene, resulting in the amino acid change G --> R at position 116 in the HN protein.

Genome sequence of the non-pathogenic strain 15 of pneumonia virus of mice and comparison with the genome of the pathogenic strain J3666

Pneumonia virus of mice (PVM) is a member of the subfamily Pneumovirinae and is the closest known relative of respiratory syncytial virus. Both viruses cause pneumonia in their respective hosts. Here, the genome sequences of two strains of PVM, non-pathogenic strain 15 and pathogenic strain J3666, are reported. Comparison of the genome sequences revealed 59 nucleotide differences between the two strains, 37 of which were coding. The nucleotide differences were spread throughout the genome, affecting cis-acting regulatory regions and seven of the ten genes. Development of a reverse-genetics system for PVM should allow further elucidation of the functional importance of the genetic differences between the two strains identified here.

Chimeric pneumovirus nucleocapsid (N) proteins allow identification of amino acids essential for the function of the respiratory syncytial virus N protein

The nucleocapsid (N) protein of the pneumovirus respiratory syncytial virus (RSV) is a major structural protein which encapsidates the RNA genome and is essential for replication and transcription of the RSV genome. The N protein of the related virus pneumonia virus of mice (PVM) is functionally unable to replace the RSV N protein in a minigenome replication assay. Using chimeric proteins, in which the immediate C-terminal part of the RSV N protein was replaced with the equivalent region of the PVM N protein, it was shown that six amino acid residues near the C terminus of the N protein (between residues 352-369) are essential for its function in replication and for the ability of the N protein to bind to the viral phosphoprotein, P.

Glucocorticoid administration accelerates mortality of pneumovirus-infected mice

The use of glucocorticoids for the treatment of symptoms associated with respiratory syncytial virus (RSV) infection has been questioned. To evaluate the sequelae of glucocorticoid administration in the setting of pneumovirus infection in vivo, hydrocortisone was administered to mice infected with pneumonia virus of mice (PVM), a pneumovirus and natural rodent pathogen that is closely related to RSV and replicates the signs and symptoms of severe human RSV infection. Results showed that hydrocortisone spared the pulmonary neutrophilia but resulted in ablation of the pulmonary eosinophilia, despite continued production of the relevant chemoattractant, macrophage inflammatory protein-1alpha. Hydrocortisone also led to diminished production of inducible nitric oxide synthase and accumulation of reactive nitrogen species in lung tissue and bronchoalveolar lavage fluid and diminished lymphocyte recruitment. PVM-infected mice responded to hydrocortisone with enhanced viral replication and accelerated mortality. These results suggest several mechanisms to explain why glucocorticoid therapy may be of limited benefit in the overall picture of pneumovirus infection.

Fidelity of leader and trailer sequence usage by the respiratory syncytial virus and avian pneumovirus replication complexes

The specificity of usage of promoters for replication and transcription by the pneumoviruses human respiratory syncytial virus (HRSV) and avian pneumovirus (APV) was studied using minigenomes containing a reporter gene. When infectious HRSV or APV was used as helper virus, replication could occur only if both the leader and trailer regions (containing the replicative and transcriptional promoters) were derived from the helper virus. In contrast, when the HRSV replication complex was supplied from cDNA plasmids, a minigenome containing either the APV leader or trailer was recognized and substantial levels of replication and transcription occurred. These data suggest that in pneumovirus-infected cells, helper virus functions can discriminate between genomes on the basis of the terminal sequences and that there is an association between the leader and trailer required for productive replication. This association is required only in virus-infected cells, not when replication and transcription are mediated by plasmid-directed expression of the component proteins required for replication and transcription. The possible implications of this are discussed.

MIP-1alpha is produced but it does not control pulmonary inflammation in response to respiratory syncytial virus infection in mice

The intent of this study was to compare the cellular and biochemical inflammatory responses of mice infected with the paramyxovirus pathogens respiratory syncytial virus (RSV) and pneumonia virus of mice (PVM). Although RSV is not a natural pathogen of mice, it has been used extensively in mouse models of the human disease, as a limited respiratory infection can be established via intranasal inoculation of virus at high titer. In earlier work, we found that acute infection with the natural rodent pathogen, PVM, elicited a rapid and sustained pulmonary inflammatory response (peak, 1.7 x 10(6) leukocytes/ml BAL fluid) that was dependent on both local production of MIP-1alpha and signaling via its receptor, CCR1. We find here that MIP-1alpha is also produced in response to RSV, although relatively few leukocytes (<200 ml BAL fluid) are recruited to the lungs in response. Further experiments with CCR1-deficient mice confirm the finding that although MIP-1alpha is produced in response to RSV infection, leukocytes do not respond via this pathway. Among the explanations for these findings, we propose that there are other, as yet to be identified proinflammatory mediators elicited in response to PVM (but not in response to RSV) that serve to prime the leukocytes in vivo, thus enabling them to respond to MIP-1alpha signaling via CCR1. Furthermore, the differences in disease pathogenesis seen in response to each of these pneumovirus infections in mice raise questions regarding the extent to which primary RSV infection in mice can be used as a model of primary RSV infection in humans.

The chemokine macrophage-inflammatory protein-1 alpha and its receptor CCR1 control pulmonary inflammation and antiviral host defense in paramyxovirus infection

In this work, we explore the responses of specific gene-deleted mice to infection with the paramyxovirus pneumonia virus of mice (PVM). We have shown previously that infection of wild type mice with PVM results in pulmonary neutrophilia and eosinophilia accompanied by local production of macrophage-inflammatory protein-1 alpha (MIP-1 alpha). Here we examine the role of MIP-1 alpha in the pathogenesis of this disease using mice deficient in MIP-1 alpha or its receptor, CCR1. The inflammatory response to PVM in MIP-1 alpha-deficient mice was minimal, with approximately 10-60 neutrophils/ml and no eosinophils detected in bronchoalveolar lavage fluid. Higher levels of infectious virus were recovered from lung tissue excised from MIP-1 alpha-deficient than from fully competent mice, suggesting that the inflammatory response limits the rate of virus replication in vivo. PVM infection of CCR1-deficient mice was also associated with attenuated inflammation, with enhanced recovery of infectious virus, and with accelerated mortality. These results suggest that the MIP-1 alpha/CCR1-mediated acute inflammatory response protects mice by delaying the lethal sequelae of infection.

Expression of the ORF-2 protein of the human respiratory syncytial virus M2 gene is initiated by a ribosomal termination-dependent reinitiation mechanism

Translation of the open reading frame 2 (ORF-2) of the human respiratory syncytial virus M2 gene initiates at one of the three initiation codons located upstream of the termination codon for the first ORF. Replacement of ORF-2 with the major ORF of the chloramphenicol acetyltransferase reporter gene followed by systematic mutagenesis of the putative initiation codons demonstrated the usage of these codons as the translational initiators for ORF-2 expression both in vitro and in vivo. While the efficiency of translation was maintained when only the first and second AUG codons were preserved in vivo, there was no apparent preference in vitro for any of the three codons when only one was present. Mutagenesis studies showed that the location of the termination codon of ORF-1 protein plays a crucial role in directing translation of ORF-2 from the upstream initiation codons in vivo. This indicates that the second ORF is accessed by the ribosomes that are departing from the first ORF and that these ribosomes reinitiate on AUG codons 5' to the point of translation termination.

Pulmonary eosinophilia and production of MIP-1alpha are prominent responses to infection with pneumonia virus of mice

Human eosinophils secrete two distinct ribonucleases that have antiviral activity against pathogens of the family Paramyxoviridae. To examine the role of eosinophils and their ribonucleases in host defense against paramyxovirus pathogens in vivo, we have developed a mouse model involving a viral pathogen that naturally targets a rodent host. In this work we describe infection of Balb/c mice with pneumonia virus of mice (PVM, strain J3666), a paramyxovirus pathogen found frequently among rodent populations. We show here that pulmonary eosinophilia is an immediate response to infection with PVM, with bronchoalveolar lavage fluid containing 12-14% eosinophils obtained as early as day 3 postinoculation. Infection is accompanied by the production of macrophage inflammatory protein-1-alpha (MIP-1alpha), a chemokine that has been associated with the pulmonary eosinophilia observed in response to respiratory syncytial virus infection in humans and with enhanced clearance of influenza virus in mice. Interestingly, we observed no changes in expression of the chemoattractants eotaxin and RANTES in response to PVM infection, and interleukin-5 remained undetectable throughout. These responses-clinical pathology, viral recovery, pulmonary eosinophilia, and production of MIP-1alpha-will provide a means for exploring the role of eosinophils, eosinophil secretory ribonucleases, and eosinophil chemoattractants in host defense against PVM and related paramyxovirus pathogens in vivo.

Matrix protein of Chandipura virus inhibits transcription from an RNA polymerase II promoter

Chandipura virus (CHPV) is a Vesiculovirus, related to, but phylogenetically distinct from, vesicular stomatitis virus (VSV). The matrix protein of VSV, as well as its role in virus assembly, inhibits the transcription from promoters for host RNA polymerases I and II. Cloning and expression of the matrix protein of CHPV in human cells showed that this protein is also functional in its inhibitory effect on transcription of a reporter gene from the cytomegalovirus immediate-early promoter, despite sharing only 28% amino acid sequence identity with the matrix protein of VSV.

A novel spliced variant of the type 1 corticotropin-releasing hormone receptor with a deletion in the seventh transmembrane domain present in the human pregnant term myometrium and fetal membranes

CRH exerts its actions via activation of specific G protein-coupled receptors, which exist in two types, CRH-R1 and CRH-R2, and arise from different genes with multiple spliced variants. RT-PCR amplification of CRH receptor sequences from human myometrium and fetal membranes yielded cDNAs that encode a novel CRH-R type 1 spliced variant. This variant (CRH-R1d) is present in the human pregnant myometrium at term only, which suggests a physiologically important role at the end of human pregnancy and labor. The amino acid sequence of CRH-R1d is identical to the CRH-R1alpha receptor except that it contains an exon deletion resulting in the absence of 14 amino acids in the predicted seventh transmembrane domain. Binding studies in HEK-293 cells stably expressing the CRH-R1d or CRH-R1alpha receptors revealed that the deletion does not change the binding characteristics of the variant receptor. In contrast, studies on the G protein activation demonstrated that CRH-R1d is not well coupled to the four subtypes of G proteins (G(s), G(i), G(o), G(q)) that CRH-R1alpha can activate. These data suggest that although the deleted segment is not important for CRH binding, it plays a crucial role in CRH receptor signal transduction. Second messenger studies of the variant receptor showed that CRH and CRH-like peptides can stimulate the adenylate cyclase system, with reduced sensitivity and potency by 10-fold compared with the CRH-R1alpha. Furthermore, CRH failed to stimulate inositol trisphosphate production. Coexpression studies between the CRH-R1d or CRH-R1alpha showed that this receptor does not play a role as a dominant negative receptor for CRH.

The integration of HPV-18 DNA in cervical carcinoma

AIMS

Little information is available on the patterns of integration into the host chromosomal DNA of cervical carcinomas of human papillomavirus type 18 (HPV-18) DNA, which is associated with up to 20% of these carcinomas. Because integration of the viral genome may be extremely important in the pathogenesis of cervical carcinoma, the aim of this study was to investigate which regions of HPV-18 DNA are integrated into the cellular DNA of cervical carcinomas.

METHODS

Southern analysis using four subgenomic probes covering the entire HPV-18 genome was used to map viral DNA integrated within cellular DNA. The polymerase chain reaction (PCR) was used to confirm the presence of specific regions of the viral genome.

RESULTS

In all 11 carcinomas there was a single major HPV-18 DNA integrant, retaining approximately 4000 bp of HPV-18 DNA, indicating that approximately half of the virus genome had been lost upon integration. Southern analysis suggested strongly that the viral breakpoint was within the E1/E2 gene boundary, with concomitant loss of part or all of the E2 ORF (open reading frame), all of the E4, E5, and L2 ORFs and part of the L1 ORF. These data were supported by the PCR results, which confirmed that the region of integrated HPV-18 DNA from nucleotides 6558 to 162 was present in all the carcinoma samples studied. Assuming that no genomic rearrangements, deletions, or insertions had occurred, 4131 bp of integrated HPV-18 DNA could be accounted for in eight cervical carcinoma samples. The results of Southern analysis also suggested that integration of HPV-18 DNA may have occurred at a specific host chromosomal site.

CONCLUSIONS

Broadly, the viral sequences retained upon HPV-18 integration resemble those found when HPV-16 is integrated. However, it appears that the HPV-18 E2 region is more consistently deleted.

Detection and characterization of proteins encoded by the second ORF of the M2 gene of pneumoviruses

The nucleotide sequence of the M2 gene of pneumonia virus of mice (PVM) was determined. The sequence showed that the gene encoded a protein of 176 amino acids with a predicted molecular mass of 20165 Da from a major ORF, which is smaller than the equivalent proteins encoded by human, bovine and ovine respiratory syncytial (RS) viruses. The PVM M2 protein is conserved, having 41% similarity to the equivalent human RS virus protein. In common with the M2 genes of the RS viruses and avian pneumovirus (APV), the PVM mRNA also contained a second ORF (ORF2) that partially overlaps the first ORF and which is capable of encoding a 98 residue polypeptide. No significant sequence identity could be detected between the putative M2 ORF2 proteins of PVM, APV and the RS viruses. The expression of the M2 ORF2 proteins of the pneumoviruses was investigated by using monospecific antisera raised against GST fusion proteins. Western blot analysis demonstrated the presence of polypeptides encoded by M2 ORF2 of PVM and RS virus corresponding with those predicted by in vitro translation studies, but this was not the case for APV. The PVM polypeptide was present as three distinct products in vivo. The PVM and RS virus polypeptides were also detected in cells by immunofluorescence, which showed that both were present in the cytoplasm with a degree of localization in inclusion bodies. No APV M2 ORF2 protein could be detected in vivo. The RS virus M2 ORF2 polypeptide was shown to accumulate during infection and the potential implications of this are discussed.

A single amino acid substitution in the phosphoprotein of respiratory syncytial virus confers thermosensitivity in a reconstituted RNA polymerase system

The single amino acid change Gly172 to Ser in the phosphoprotein (P) of respiratory syncytial virus (RSV) has previously been shown to be responsible for the thermosensitivity and protein-negative phenotype of tsN19, a mutant of the B subgroup RSN-2 strain. This single change was inserted into the P gene of the A subgroup virus RSS-2, and the resulting phenotype was observed in a plasmid-driven reconstituted RSV RNA polymerase system. Expression from a genome analogue containing two reporter genes was thermosensitive when directed by plasmids containing the N, L, M2, and mutant P genes cloned under the control of T7 promoters. Analysis of RNA synthesis showed that mutant P protein was unable to produce genome, antigenome, or mRNA at the restrictive temperature. At a semipermissive temperature, genome, antigenome, and mRNA synthesis were all reduced, 6- to 30-fold, relative to synthesis directed by a wild-type P plasmid. Binding of the mutant P protein to N protein in the absence of other viral proteins was unaffected by temperature, indicating that the lesion did not produce a large enough structural change to disrupt this binding. These data suggest that the plasmid rescue system is suitable for investigation of the role of thermosensitive mutations in RSV polymerase components in RNA synthesis.

Pathogenesis of pneumovirus infections in mice: detection of pneumonia virus of mice and human respiratory syncytial virus mRNA in lungs of infected mice by in situ hybridization

The pathogenesis of pneumonia virus of mice (PVM) and human respiratory syncytial virus (HRSV) in BALB/c mice were investigated by using in situ hybridization to detect virus mRNA in fixed lung sections. Following intranasal inoculation with 120 p.f.u. PVM the pattern of hybridization showed that virus mRNA was initially detected within 2 days in alveolar cells. As the infection progressed the number of hybridizing alveolar cells increased and signal was also detected in cells lining the terminal bronchioles. By days 4 to 5 post-infection areas of morphological abnormality could be seen, particularly in the strongly hybridizing regions of the lung, and this correlated with the appearance of clinical signs of infection. In animals which survived the infection virus-specific mRNA could not be detected 10 days post-infection. Mice infected with 1500 p.f.u. HRSV showed significant differences in the distribution of virus-specific mRNA when compared to the pattern seen with PVM. HRSV mRNA was detected over large areas, but predominantly in peribronchiolar and perivascular regions of the lungs 5 days post-infection. The yield of PVM from infected mouse lungs was considerably higher than that of HRSV. The possible implications of these results for the use of the mouse model for pneumovirus infections are discussed.

Human corticotropin-releasing hormone receptor: differences in subtype expression between pregnant and nonpregnant myometria

There is increasing evidence that CRH, which is the principal neuroregulator of the hypothalamic-pituitary-adrenocortical axis, is also involved in the mechanism of human labor. The human myometrium has been shown to express several high affinity CRH receptors, although the identities of the CRH receptor subtypes have yet to be identified. To investigate further the expression of the CRH receptor in human myometrium, we used RT-PCR, fluorescent in situ hybridization and immunofluorescence to identify and localize the four subtypes, 1 alpha, 1 beta, 2 alpha, and the variant C, of the CRH receptor. Interestingly, the CRH receptor subtypes in myometrium exhibit differential expression patterns; in human pregnant myometrium at term all four receptor-subtypes were expressed, whereas only the 1 alpha- and 1 beta-receptor subtypes were found in the nonpregnant myometrium. This would suggest that CRH, acting via different receptor subtypes, is able to exert different actions on the myometrium in the pregnant state compared to the nonpregnant state. Furthermore, in the pregnant human uterus, CRH receptors were localized in both smooth muscle and fibroblasts. These findings suggest that CRH receptor expression plays an important modulatory role in myometrial and possibly in cervical function.

Characterization of the interaction of the human respiratory syncytial virus phosphoprotein and nucleocapsid protein using the two-hybrid system

The interaction between the human respiratory syncytial virus phosphoprotein (P) and nucleocapsid (N) protein has been investigated using the two hybrid system in yeast and in tissue culture cells. Deletion analysis identified two regions in the P protein involved in this interaction. The immediate carboxy-terminal 20 amino acids were essential for interaction with the N protein. Point mutations in this region demonstrated that alteration of two conserved, phosphorylated, serine residues reduced binding to 50% of that of the native protein. The introduction of two proline residues to disrupt the predicted alpha-helical domain in this region dramatically reduced the ability of the mutant P protein to interact with the N protein. A second region which affected the interaction of the two proteins was located adjacent to the essential carboxy-terminal area. Deletion of this second region resulted in an increase in the strength of the interaction between the two proteins. These data shows that the RSV P protein, while having no amino acid sequence identity with the equivalent P protein of other negative strand viruses, is likely to have similar structural and functional features.

Rescue of synthetic minireplicons establishes the absence of the NS1 and NS2 genes from avian pneumovirus

We have determined the nucleotide sequences of the regions 3' and 5' proximal to the avian pneumovirus (APV) N and L genes, respectively. These sequences were used in the construction of a synthetic minireplicon construct in which the chloramphenicol acetyltransferase (CAT) reporter gene was flanked at its 3' end with the APV leader together with the APV N gene start signal and at its 5' end with the APV L gene end signal and the genome trailer region. The ability of T7 RNA polymerase runoff transcripts to direct the replication and expression of the CAT reporter gene in APV-infected cells demonstrated the ability of the putative leader and trailer regions to direct genome replication and gene expression. Furthermore, this confirms the absence of the NS1 and NS2 gene analogs within the APV genome. We were able to detect the expression of CAT protein from cells that had been infected with supernatants from the initially infected and transfected cells. These results have identified the cis-acting sequences of APV responsible for viral replication, gene expression, and packaging into virus-like particles.

Nucleotide sequence of the genes encoding the matrix and small hydrophobic proteins of pneumonia virus of mice

The nucleotide sequences of the genes encoding the matrix (M) protein and the small hydrophobic (SH) protein of pneumonia virus of mice (PVM) are described. The matrix protein gene contains a large open reading frame encoding polypeptide of 257 residues which shows considerable (38.6-42.1%) amino acid identity with the matrix proteins of other pneumoviruses. The matrix gene also contains a second, smaller, open reading frame (ORF) as seen with the equivalent genes of other pneumoviruses. The PVM second open reading frame is capable of encoding a polypeptide of 46 residues and shows no significant similarity with the proteins encoded by the equivalent open reading frames of the other pneumoviruses. The gene adjacent to that encoding the matrix protein encodes a small, 92 residue, polypeptide which has a central hydrophobic domain and is structurally similar to the small hydrophobic protein of respiratory syncytial virus.

Nucleotide sequence of the gene encoding the viral polymerase of avian pneumovirus

We report here the nucleotide sequence of the L gene of avian pneumovirus (APV). This is the second pneumovirus L gene and the second avian paramyxovirus L gene, following that of Newcastle disease virus, to be sequenced. The APV L gene is 6099 nucleotides long and encodes a single large ORF of 2004 amino acids. This makes the APV L protein the smallest to be described for any nonsegmented, negative-strand RNA virus. The protein contains six linear non-contiguous domains, a putative ATP-binding site and four polymerase motifs previously described for the L proteins of negative-strand RNA viruses. Phylogenetic analysis of domain III of 14 different L proteins suggests the pneumoviruses to be as distant in evolutionary terms from the other members of the Paramyxoviridae as are the Filoviridae.

Identification of mutations contributing to the reduced virulence of a modified strain of respiratory syncytial virus

The nucleotide sequences of the genome of the RSS-2 wild type strain of respiratory syncytial (RS) virus, which is known to induce upper respiratory tract infection in adults, and that of the attenuated ts1C candidate vaccine derived from it by three cycles of mutagenesis and selection of temperature-sensitive (ts) mutants, have been determined. Comparison of the sequences has located the genetic changes which contribute to the reduced pathogenicity in adults of the candidate vaccine. Thirty-seven nucleotide changes distinguish the wild type and ts1C, 13 of which confer amino acid substitutions; no mutations are present in extragenic regions. Partial nucleotide sequencing of the genomes of the first stage ts mutant (ts1A) and the second stage ts mutant (ts1B), which were intermediates in the derivation of the third stage mutant ts1C, established that five mutations resulting in amino acid substitutions had been induced in the first cycle of mutagenesis, one in the second cycle, and seven in the third cycle. The unique mutation differentiating ts1B from ts1A substitutes an alanine for a threonine at residue 736 in the polymerase (L) protein. The occurrence of a mutation in ts1C inducing substitution of a phenylalanine for a serine residue at an adjacent site (731) suggests that mutations in this region of the polymerase can have significant attenuating effects. The data suggest also that a mutation in the F gene may contribute to the attenuated phenotype.

Sequence of the nucleocapsid protein gene of subgroup A and B avian pneumoviruses

The nucleocapsid protein (N) gene of two subgroup A and one subgroup B strains of avian pneumovirus has been cloned and sequenced. The gene of all three isolates comprised 1197 nucleotides (nt), which formed a single major open reading frame, potentially encoding a protein of 391 amino acid residues. The N gene of the two subgroup A isolates differed by only 1 nt but differed by 282 (24%) nt and 35 (11%) amino acids from the B isolate. The predicted protein was identical in length to that of human, bovine and ovine respiratory syncytial viruses, the amino acid identity being approximately 41% overall but with some regions of identity > 90%.

Nucleotide sequence of the matrix protein gene of a subgroup B avian pneumovirus

The nucleotide sequence of the gene encoding the matrix protein of a subgroup B avian pneumovirus has been determined. The gene shows 73.5% homology with that of a subgroup A virus, with most differences occurring in the third codon position. Comparison with pneumovirus matrix proteins shows that the APV matrix protein retains the hydrophobic domain common to the others. The analysis indicates that the matrix protein gene can be used to differentiate the two APV subgroups.

Characterisation of the interaction between the nucleoprotein and phosphoprotein of pneumonia virus of mice

A protein blotting technique was used to study the interaction occurring between the pneumonia virus of mice N protein and other PVM encoded proteins expressed in infected cells. Measurement of the degree of binding indicated that the N protein specifically interacted only with the full-length 39 kDa P protein in infected cells. Truncated N-related proteins were synthesised in vitro and incubated with filter-bound full-length and truncated P proteins. The data suggested that many regions of the N protein are cooperatively involved in the binding process. It was also determined that both the amino and the carboxyl-terminal regions of the PVM P protein were essential for binding to N protein.

Sequence variation in the haemagglutinin-neuraminidase gene of human parainfluenza virus type 3 isolates in the UK

The sequence variation in a 934 base-pair region of the gene encoding the haemagglutinin-neuraminidase of five human parainfluenza virus type 3 (HPIV3) isolates was determined together with that of a prototype UK strain. All of the clinical isolates were from the Manchester area of the UK and were obtained in 1990, 1991 and 1993. The gene segment was amplified by the polymerase chain reaction using HPIV3-specific oligonucleotide primers. The nucleotide homology of the strains was high, around 99% and specific differences in the UK sequences when compared with that of the US prototype strain were identified. In addition, a number of isolate-specific differences were seen. No correlation was detected between the observed nucleotide mutations and the year of isolation, which supports the hypothesis that HPIV3 shows cocirculation of a heterogeneous population of viruses rather than varying with time in a linear fashion. However, the data suggested that geographically-defined genetic lineages of HPIV3 may exist.

Sequence and in vitro expression of the phosphoprotein gene of avian pneumovirus

The phosphoprotein (P) gene of two subgroup A strains of avian pneumovirus comprised 855 nucleotides containing only one substantial open reading frame encoding a protein of 278 amino acids, with a predicted M(r) of 30,323. In vitro translation of P mRNA in a wheat germ system resulted in the synthesis of two polypeptides of M(r) 35,000. Comparison of the deduced P protein sequence with that of the known mammalian pneumoviruses revealed overall amino acid identities ranging from 31 to 34.5%, suggesting a distant relationship. However, there was a much higher identity (63.2-68.4%) in a region of 57 residues, which included a heptad repeat sequence.

Nucleotide sequences of the genes encoding the putative attachment glycoprotein (G) of mouse and tissue culture-passaged strains of pneumonia virus of mice

The sequences of the genes encoding the putative attachment (G) proteins of pathogenic (strain J3666) mouse lung-passaged and nonpathogenic (strain 15) tissue culture-passaged strains of pneumonia virus of mice (PVM) have been determined. In both cases the major polypeptide was synthesised from the second open reading frame (ORF), a feature also found in the G gene of respiratory syncytial (RS) virus, another pneumovirus. However, the ORFs of the G genes of the two PVM strains were initiated at different nucleotide positions in the mRNA and comparison of hydrophobicity profiles revealed the presence of the putative amino-terminal cytoplasmic domain in the strain J3666 G protein and its absence in the predicted G protein of PVM strain 15. In common with the G protein of RS virus, the gene product of both PVM strains contained a high serine, threonine, and proline content. Indirect immunofluorescence analysis of BSC-1 cells expressing the G gene products confirmed the surface location of the proteins. Thus, the absence of a cytoplasmic domain does not interfere with the translocation of the G protein of PVM strain 15. In vitro translation of mRNA from the two PVM genes directed the synthesis of a larger polypeptide with the G gene of PVM strain J3666 than was seen with strain 15 G gene. In addition, a second protein was seen with strain J3666 mRNA which was the same size as the strain 15 G protein.

Extensive sequence variation in the attachment (G) protein gene of avian pneumovirus: evidence for two distinct subgroups

The putative attachment protein of the avian pneumovirus that causes turkey rhinotracheitis is, by analogy with mammalian pneumoviruses, expected to be the major antigenic determinant. We report the nucleotide sequence of the attachment (G) protein genes of five different continental European isolates and compare them with the previously published sequence of the G gene for the focal variant of a U.K. isolate. The nucleotide sequences and the predicted amino acid sequences indicate that there are at least two distinct subgroups, similar to the grouping described for human respiratory syncytial (RS) virus. The U.K. and French isolates form one group and the isolates from Spain, Italy and Hungary form a second. The two subgroups can be easily distinguished on the basis of restriction enzyme digestion of PCR-generated products representing the full-length gene. Within the subgroups the predicted G proteins were highly conserved (98.5 to 99.7% amino acid identity) compared to the levels of identity of RS virus G proteins in the same subgroup (80 to 95%). Between the avian pneumovirus subgroups described here there was an unexpected degree of divergence, the average amino acid identity between members of the two groups being only 38%. This compares with the 53% conservation seen between members of the RS virus subgroups A and B. Comparison of the predicted amino acid sequences showed that the G proteins of members of the two avian pneumovirus subgroups had similar structural features. All proteins had an amino-terminal membrane anchor and the positions of cysteine residues were highly conserved. The potential importance of the high level of variation between the two subgroups in terms of epidemiology of the disease is discussed.

Characterization of the minimal elements of the hepatitis B virus large surface antigen promoter

It has been demonstrated that the hepatocyte nuclear factor 1 (HNF1) binding site is critical for the majority of the hepatitis B virus (HBV) large surface antigen promoter activity in differentiated hepatoma cell lines. Examination of a series of clustered point mutations in the minimal large surface antigen promoter demonstrated that the HNF1 and TATA box binding sites are the major regulatory elements required for transcription from this promoter. Synthetic promoter constructs containing the large surface antigen promoter HNF1 binding site and TATA box element upstream of the luciferase open reading frame were tested for their transcriptional activities in HepG2. 1 cells in the absence or presence of an HNF1 expression vector. These synthetic promoter constructs displayed a similar level of transcriptional activity and induction by HNF1 in comparison with the full-length large surface antigen promoter, suggesting that additional HBV sequences are dispensable for full transcriptional activity. The distance between the HNF1 binding site and TATA box element in the synthetic promoter constructs appeared to influence the transcriptional activity modestly and in a periodic manner.

Sequence of the phosphoprotein gene of pneumonia virus of mice: expression of multiple proteins from two overlapping reading frames

The gene encoding the phosphoprotein of the pneumovirus pneumonia virus of mice (PVM) has been cloned and sequenced. The gene is 903 nucleotides in length and contains a long open reading frame (ORF) capable of encoding a polypeptide of 295 amino acid residues. A smaller, second, overlapping ORF encoding a polypeptide 137 amino acids in length was also present. The large ORF directed the synthesis of a 39-kDa polypeptide and four additional polypeptides with masses of 37 kDa, 26 kDa, 23 kDa, and 16 kDa in vitro. The smaller polypeptides were generated by internal initiation on in-frame AUG initiation codons to generate carboxy co-terminal products. Western immunoblot analysis indicated that at least two of these proteins and several other related polypeptides are present in infected cells, and the possible origins of these are discussed. Western blot analysis using antiserum raised against a synthetic peptide and specific for the predicted second ORF product identified a polypeptide of 23 kDa in PVM-infected cells. The pattern of PVM P gene expression is unlike that of the closely related respiratory syncytial virus and is reminiscent of that of paramyxoviruses such as Sendai virus. This is the first example of a pneumovirus encoding multiple polypeptide products from a single mRNA in vivo.

3' terminal nucleotide sequence of human astrovirus type 1 and routine detection of astrovirus nucleic acid and antigens

Human astrovirus type 1 was purified by caesium chloride density-gradient centrifugation and the virus was located using an immunodot blot technique with polyclonal rabbit serum, which reacted with all five serotypes. The virus banded with a density of 1.33 g/ml. RNA was extracted from the purified virus, converted into double-stranded cDNA, using an oligo(dT) primer, and cloned into plasmid and M13 vectors. The sequence of the 3' end of astrovirus RNA adjacent to the poly(A) tract was determined. This sequence showed no significant homology with the equivalent region of other positive-sense RNA viruses. Synthetic oligonucleotide primers were designed to amplify specifically astrovirus type 1 RNA in a polymerase chain reaction.

Sequence analysis of the 22K, SH and G genes of turkey rhinotracheitis virus and their intergenic regions reveals a gene order different from that of other pneumoviruses

The nucleotide and deduced amino acid sequences of three genes of turkey rhinotracheitis virus (TRTV) together with the nucleotide sequences of the relevant intergenic regions were determined. The deduced amino acid sequence of one of the genes shows significant identity (42%) to that of the 22K protein of human respiratory syncytial virus (RSV). The TRTV 22K gene, like that of RSV, has a second open reading frame, although the amino acid sequence deduced from this reading frame does not show any similarity to the equivalent predicted RSV protein. The other two genes and their deduced amino acid sequences do not show any sequence similarity to the genes of other pneumoviruses. However, the hydrophobicity profiles of the predicted proteins do show similarities to those of the small hydrophobic (SH) and attachment protein (G) genes of RSV. The TRTV G gene is 1193 nucleotides in length and encodes a protein of 391 amino acids (M(r) 42984), which is rather larger than the RSV G protein (predicted M(r) 36000). The TRTV SH gene is 589 nucleotides in length, encoding a protein of 174 amino acids (M(r) 18797), which is considerably larger than the size of the RSV SH protein (M(r) 7500). The sequences of the intergenic regions derived from clones of polycistronic mRNAs and polymerase chain reaction products obtained with primers from different genes reveal the order on the virus genome to be 3' F-22K-SH-G 5'. This differs from the gene order of paramyxoviruses and morbilliviruses, which lack a 22K gene (and in some cases a SH gene), and the pneumoviruses RSV and pneumonia virus of mice, which have the F and 22K genes located after the G gene.

Sequence analysis of the gene encoding the fusion glycoprotein of pneumonia virus of mice suggests possible conserved secondary structure elements in paramyxovirus fusion glycoproteins

The gene encoding the fusion (F) glycoprotein of pneumonia virus of mice consists of 1657 bases and contains an open reading frame encoding 537 amino acids which is more similar to the F proteins of pneumoviruses than to those of other paramyxoviruses. Computer-assisted sequence analyses can be combined with data on the antigenicity of various F proteins to suggest a possible arrangement of secondary structure elements common to all pneumovirus and paramyxovirus F proteins.

Promoter-specific transactivation of hepatitis B virus transcription by a glutamine- and proline-rich domain of hepatocyte nuclear factor 1

The cloned transcription factor hepatocyte nuclear factor 1 (HNF1) transactivates transcription from the hepatitis B virus (HBV) large surface antigen promoter but does not influence the transcriptional activities of the other three HBV promoters. This indicates that this transcription factor can differentially influence the activities of the HBV promoter. By using a transient-transfection system, the major domain of the HNF1 polypeptide involved in transcriptional activation of the large surface antigen promoter in the human hepatoma cell line HepG2.1 has been mapped to a region that is rich in glutamine and proline residues (9 of 18) and is different from the previously identified regions of this factor responsible for in vitro transcriptional activation of a promoter containing human albumin promoter HNF1 binding sites. The human albumin promoter HNF1 binding site mediates transcriptional activation through the same HNF1 polypeptide domain as the HBV large surface antigen promoter HNF1 binding site in transient-transfection assays with HepG2.1 cells, suggesting that HNF1 may possess multiple transcriptional activation domains.

Genes 1 and 2 of pneumonia virus of mice encode proteins which have little homology with the 1C and 1B proteins of human respiratory syncytial virus

Genes 1 and 2 of pneumonia virus of mice (PVM) consist of 410 and 571 nucleotides and encode proteins of 113 and 156 amino acids respectively. The proteins show no extensive (gene 1 analogous to 1C) or low (gene 2 analogous to 1B) homology to their presumed counterparts in human respiratory syncytial virus (HRSV). The strongest homology is between regions of approximately 35 amino acids located near the carboxy termini of the gene 2 product and the 1B protein with 29% identity, although a lower level of homology can be detected throughout much of these proteins (18% identity overall). These observations contrast with the conservation of 1C and 1B proteins between subgroups of HRSV and with the conservation of nucleocapsid proteins between HRSV and PVM.

Coxsackie virus B4 infection of the mouse pancreas: I. Detection of virus-specific RNA in the pancreas by in situ hybridisation

The pathology of Coxsackie virus B4 (CVB4) infection in a murine model was investigated by in situ hybridisation using a biotinylated cDNA probe derived from CVB4. During the acute phase of infection virus RNA sequences were detected in the exocrine pancreas of 60% of mice infected with a pancreotropic variant of CVB4. A positive hybridisation signal was observed in other organs in some animals including the heart and liver of 1 mouse 28 days after infection. The cellular distribution of virus RNA sequences corresponded well with the histological findings in most tissues. Possible causes for failure of hybridisation in some infected pancreases are discussed in conjunction with potential application of the technique in human pancreas biopsy samples.

The nucleotide sequences of intergenic regions between nine genes of pneumonia virus of mice establish the physical order of these genes in the viral genome

We have cloned eight intergenic regions from the Pneumovirus pneumonia virus of mice that link the nine small and medium sized genes previously described (Chambers et al., 1990). The nucleotide sequences of the clones confirm the locations of these genes and their mRNA transcripts in the viral genome. The intergenic regions vary in size from 2-56 nucleotides and show only faint homology to each other or to their analogues in respiratory syncytial virus. Sequence alignments suggest that the location of the transcriptional start site for the mRNA encoding the major nucleocapsid protein of pneumonia virus of mice and respiratory syncytial virus may have altered during virus evolution by gain or loss of a transcriptional start signal.

Sequence of the major nucleocapsid protein gene of pneumonia virus of mice: sequence comparisons suggest structural homology between nucleocapsid proteins of pneumoviruses, paramyxoviruses, rhabdoviruses and filoviruses

The complete nucleotide sequence of gene 3 of pneumonia virus of mice has been determined, and the 5' end of the mRNA mapped using a modification of the polymerase chain reaction technique. The gene contains a single open reading frame, beginning with a 5'-proximal AUG initiation codon, encoding a polypeptide with a predicted Mr of 43141. Expression of the gene 3 protein in Escherichia coli and in vitro showed that it reacted with virus-specific antiserum and comigrated with the major nucleocapsid (N) polypeptide. The predicted amino acid sequence has extensive identity with that of the N protein of human respiratory syncytial virus. Comparisons with the amino acid sequences of N proteins of other paramyxoviruses, vesicular stomatitis virus and Ebola virus suggest that these proteins may have retained much of the same structure. These regions of conserved structure would most likely have the common functions of RNA binding and protein/protein interactions in the virus nucleocapsid.

Heptad repeat sequences are located adjacent to hydrophobic regions in several types of virus fusion glycoproteins

Extensive regions of heptad repeat units consistent with an alpha-helical coiled coil conformation are located adjacent to hydrophobic, potentially fusion-related regions in the amino acid sequences of paramyxovirus fusion and retrovirus envelope glycoproteins. Similar arrangements of hydrophobic peptides and heptad repeat units exist in coronavirus peplomer proteins and influenza virus haemagglutinins. This suggests that there may be similarities in the structures of these proteins and in the functions of the hydrophobic fusion-related regions during virus entry.

Differentiation-specific transcriptional regulation of the hepatitis B virus large surface antigen gene in human hepatoma cell lines

The transcriptional activities of the four hepatitis B virus promoters were compared in three differentiated hepatoma cell lines, HepG2, Hep3B, and PLC/PRF/5; a dedifferentiated subline of HepG2, HepG2.1; a human cervical carcinoma cell line, HeLa S3; and a mouse fibroblast cell line, NIH 3T3. The plasmid constructs, which contain the complete hepatitis B virus genome directing the expression of the luciferase reporter gene, were analyzed by transient transfection assays. The relative orders of the levels of the transcriptional activities of the four promoters were similar in each of the cell lines. The major surface antigen and X-gene promoters displayed the highest activity levels, the core promoter activity level was less than or similar to the activity levels of these two promoters, and the large surface antigen promoter had the lowest activity level in all of the cell lines examined. The core promoter demonstrated an approximately 2- to 20-fold higher relative level of expression in the differentiated hepatoma cell lines, suggesting that this promoter might be preferentially active in these cells. The relative level of activity of the large surface antigen promoter in the differentiated hepatoma cell lines was approximately 5 to 90 times greater than that observed in the other cell lines, indicating that the activity of this promoter is highly specific for differentiation state and cell type. Deletion analysis of the large surface antigen promoter demonstrated that the sequence element responsible for the differentiation state-specific expression from this promoter is located between nucleotides 2719 and 2733 (-90 and -76). Within this sequence element is a binding site (GTTAATCATTACT) for the liver-specific transcription factor hepatocyte nuclear factor 1 (HNF1). This indicates that the preferential expression from the large surface antigen promoter in the differentiated hepatoma cell lines is probably mediated by HNF1 or an HNF1-related transcription factor.

Molecular cloning of pneumonia virus of mice

cDNA clones representing nine genes of pneumonia virus of mice (PVM) have been generated. The sizes of the corresponding mRNAs and a provisional transcriptional map of the virus genome have been determined. The apparent gene order is very similar to that of respiratory syncytial virus. The sequences adjacent to the 3' termini of the PVM genes were determined and are very similar to those of respiratory syncytial virus. Several PVM gene polypeptide products have been assigned.