Endogenous retroviral elements in the canine genome

Defective endogenous retroviral elements have recently been found in a canine lymphosarcoma (LSA) cell line and we have characterized these by DNA sequencing. This study was designed to determine if similar elements are present in naturally-occurring canine LSAs or in normal canine DNA. Two probes were prepared by sub-cloning sequences from the 5' and 3' ends of the canine endogenous retroviralpol gene. Probes were chosen from areas sharing at least 60% homology and complete colinearity with AKV murine leukemia virus. High molecular weight genomic DNA was prepared from a variety of canine tissues: 12 samples were from LSA lymph nodes, 2 from lymphoblasts in cases of acute lymphoblastic leukemia and 7 from normal kidney. Genomic DNA was digested with restriction endonucleases and fragments were separated by agarose gel electrophoresis. Southern transfer and hybridization under stringent conditions with the canine retroviral probes revealed numerous retroviral bands. The pattern of bands was identical for all tissues examined. Similar treatment of DNA from the original LSA cell Line from which the probes were derived produced an identical pattern of bands. In summary, canine DNA has been shown to contain multiple copies of endogenous retroviral elements. No difference in the pattern of proviral bands has been observed between normal and LSA tissues, so no etiological significance can yet be ascribed to these elements. Further studies are in progress to determine whether any of these elements erpress themselves at the RNA or protein level

Phase-field approach to heterogeneous nucleation

We consider the problem of heterogeneous nucleation and growth. The system is described by a phase field model in which the temperature is included through thermal noise. We show that this phase field approach is suitable to describe homogeneous as well as heterogeneous nucleation starting from several general hypotheses. Thus we can investigate the influence of grain boundaries, localized impurities, or any general kind of imperfections in a systematic way. We also put forward the applicability of our model to study other physical situations such as island formation, amorphous crystallization, or recrystallization.Comment: 8 pages including 7 figures. Accepted for publication in Physical Review

The Concept of Governance in the Spirit of Capitalism

Through combining insights from political economy and sociology, this article explains the early genesis of the policy notion of governance in relation to ideological changes in capitalism. Such an approach has tended to be neglected in existing conceptual histories, in the process, undermining a sharper politicization of the term and how it became normalized. The argument dissects how the emergence of governance can be understood in light of a relationship between political crises, social critique and justificatory arguments (centered around security and justice claims) that form part of an ideological ‘spirit of capitalism’. Through a distinctive comparison between the creation of ‘corporate governance’ in the 1970s and the formulation of a ‘governance agenda’ by the World Bank from the 1980s, the article elucidates how the concept, within certain policy uses, but by no means all, can reflect and help constitute a neoliberal spirit of capitalism

Feline leukaemia viruses: molecular biology and pathogenesis

The feline leukaemia virus (FeLV) group represents one of the most important viral pathogens of the domestic cat. In addition, this virus - host system is one of the major experimental models for retroviral pathogenesis. Under natural conditions, the virus is horizontally transmitted through the cat population. The outcome of infection depends on a variety of factors including the virus does encountered and the age and immune status of the host. FeLVs can establish persistent infection, either overt or latent. Degenerative diseases of the haemopoietic system are the most common result of persistent infection and immunosuppression with secondary infection accounts for more deaths than does neoplastic disease. However, more is known about the molecular mechanisms of oncogenesis in this system and there are now numerous examples of field case tumours where FeLV has transduced an oncogene or acted as an insertional mutagen. The factors affecting the relative frequency of these mechanisms are considered as is the possibility that recombinant env gene recombinants play a role in FeLV pathogenesis

Polypeptides of feline leukaemia virus: identification of p15(E) and p12(E)

Antiserum to the p15(E) polypeptide of Rauscher murine leukaemia virus (R-MuLV) precipitated two proteins from purified virions of feline leukaemia virus (FeLV) with apparent mol. wt. of 18500 and 15500 on SDS-polyacrylamide gels. These proteins have been designated p15(E) and p12(E), in line with the nomenclature for MuLV proteins. Like the analogous protein of MuLV, FeLV p15(E) was found to be disulphide-linked to the virion glycoprotein, gp70. FeLV p15(E) was sensitive to digestion of intact virus particles with the proteolytic enzyme, bromelain, indicating that this protein is on the outer surface of the virion. An analysis of cat sera for precipitating activity for FeLV p12(E) showed this only in sera from cats which had recovered from FeLV infection and had virus-neutralizing activity

Transgenic science

The ability to manipulate the genome of the whole animal has, for the past 10 years, provided researchers with an alternative route of inquiry into many complex biological processes. Transgenic animals have numerous applications, encompassing a wide range of different disciplines, but they have proved especially useful in the investigation of gene regulation and gene function within the context of the living animal. This review describes the different techniques which have been used to produce transgenic animals and highlights advances which have been achieved using the transgenic approach

Defective endogenous retroviral elements in a canine lyphosarcoma cell line

A canine lymphosarcoma (LSA) cell has has been reported to produce particles with properties characteristic of mammalian retroviruses. However, it has proved difficult to reproduce this result. To search for retroviral proviral elements in this cell h e a bacteriophage Lambda genomic DNA library was made. The library was probed with a murine retrovirus (FMuLV) and hybridizing phage plaques were picked. DNA extracted from hybridizing phages was digested with restriction endonucleases and fragments were separated by agarose gel electrophoresis. Southern transfer and hybridization with FMuLV and baboon endogenous retrovirus (BaEV) revealed that 2 phage clones contained fragments which hybridized strongly with both FMuLV and BaEV. These fragments were subcloned into the plasmid vector "Bluescript" and sequenced by the dideoxy chain termination method.\ud \ud DNA sequence analysis identified 2 distinct elements homologous with a variety of retroviruses.The larger fragment (2.5 kilobase pairs) contained 1.5kbp of a defective retroviral pol gene sharing 63% homology at the DNA level with AKV murine leukemia virus. The smaller fragment (0.45kb) consisted exclusively of retroviral pol gene almost identical to that in the large fragment, but with an additional 4Obp deletion. Sequencing on either side of these fragments is continuing.\ud \ud In summary, defective endogenous retroviral elements have been found in a canine LSA cell he. The elements differ in their defects but appear otherwise to be closely related. Because of their defects, these elements could not be responsible for the production of intact retroviruses as reported in this cell line. Further study is in progress to determine whether other endogenous elements capable of producing intact retroviruses are present in this cell line. It is of interest to determine the prevalence of retroviral elements in normal canine DNA and to investigate whether they are of etiological significance in canine diseases

Skewed TCR Vbeta 8.2 usage in transgenic CD2-myc induced thymic lymphoma: a role for antigen stimulation in tumour development

No abstract available

Activation of gene expression by human herpesvirus 6 is reporter gene-dependent

Infection with human herpesvirus 6 (HHV-6) was found to up-regulate expression of human immunodeficiency virus and human T cell leukaemia virus type I (HTLV-I) long terminal repeat sequence (LTR), and herpes simplex virus type 1 (HSV-1) gD chloramphenicol acetyltransferase (CAT) constructs transfected into the T cell line, J. Jhan. Activation by HHV-6 was due to one or more viral proteins produced early in infection and, in the case of the HTLV-I LTR, was synergistic to induction mediated by the HTLV-I tax gene product. Neither the HTLV-I enhancer nor basal promoter elements of the HSV-1 gD gene were essential for activation and no increase in accumulated HTLV-I mRNA was observed due to HHV-6 infection. Induction by HHV-6 was found to be dependent on the reporter construct used, because the CAT gene and, to a lesser extent, the HSV-1 thymidine kinase gene were responsive to HHV-6 infection although no significant activation of growth hormone constructs was observed. Our results bear a strong resemblance to those obtained for the Epstein-Barr virus BMLF1 gene, indicating that the major HHV-6 trans-activator may be a homologue of this gene