Papers by Ginette Dambrine
Annales de recherches vétérinaires. Annals of veterinary research
The Journal of general virology, 2001
The avian herpesvirus Marek's disease virus (MDV) has a worldwide distribution and is respons... more The avian herpesvirus Marek's disease virus (MDV) has a worldwide distribution and is responsible for T-lymphoma in chickens. The question as to whether MDV poses a public health hazard to humans was first raised when the virus was isolated in 1967. However, no irrefutable results have been obtained in immunological and virological studies. We used a nested-PCR to detect MDV DNA in human serum samples. A total of 202 serum samples from individuals exposed and not exposed to poultry was tested by nested-PCR for a target sequence located in the MDV gD gene. The assay system was specific and sensitive, making it possible to detect a single copy of the target sequence. Forty-one (20%) of the 202 serum samples tested positive for MDV DNA. The prevalence of MDV DNA was not significantly different in the group exposed to poultry and the group not exposed to poultry. There was also no difference due to age or sex. Alignment of the 41 gD sequences amplified from human sera with eight gD ...
Virology, 2003
The molecularly cloned myeloblastosis-associated virus type-1(N) (MAV-1(N)) strain induces specif... more The molecularly cloned myeloblastosis-associated virus type-1(N) (MAV-1(N)) strain induces specifically nephroblastomas in chicken. MAV-induced nephroblastoma constitutes a unique animal model of the human Wilms' tumor. We have previously shown that the MAV-1(N) long terminal repeats (LTR) were necessary and sufficient for nephroblastoma induction. Since major determinants for oncogenesis have been mapped in the U3 region of several other retroviruses, we have analyzed the tumorigenic potential of five recombinant viruses partially deleted in their U3 region. The results obtained indicated that deletions of the LTRs resulted in a modification of the pathogenic spectrum of MAV-1(N) and a decreased efficiency for nephroblastoma induction.
Transgenic Research, 1995
We have used vectors derived from avian leukosis viruses to transduce exogenous genes into early ... more We have used vectors derived from avian leukosis viruses to transduce exogenous genes into early somatic stem cells of chicken embryos. The ecotropic helper cell line, Isolde, was used to generate stocks of NL-B vector carrying the Neo r selectable marker and the Escherichia coli lacZ gene. Microinjection of the NL-B vector directly beneath unincubated chicken embryo blastoderms resulted in infection of germline stem cells. One of the 16 male birds hatched (6.25%) from the injected embryos contained vector DNA sequences in its semen. Vector sequences were transmitted to G1 progeny at a frequency of 2.7%. Neo r and lacZ genes were transcribed in vitro in chicken embryo fibroblast cultures from transgenic embryos of the G2 progeny.
Occupational and Environmental Medicine, 1996
Objectives-To compare the prevalence of antibodies against Marek's disease herpes virus (MDV) and... more Objectives-To compare the prevalence of antibodies against Marek's disease herpes virus (MDV) and against avian leukosis viruses type C (ALV) in groups of workers exposed to poultry and in unexposed groups. Methods-Antibodies directed against avian viral proteins were detected by enzyme linked immunosorbent assay in 549 subjects. Exposure to chickens was high in two subgroups: farmers on intensive chicken farms and workers at chicken slaughterhouses. One subgroup, traditional farmers on dairy or pig farms with poultry, had moderate exposure to poultry. Another subgroup, farmers and slaughterhouse workers on quail farms, had high exposure to quails. Three subgroups were not exposed to chickens: farmers on dairy or pig farms without poultry, workers at cattle slaughterhouses, and white collar workers. Also, MDV antibodies were tested after serum sample adsorption with chicken antigens in 134 serum samples. Results-The prevalence of antibodies against MDV was significantly higher in the exposed subgroups than in unexposed groups (odds ratio (OR) 6'17; 95% confidence interval (95% CI) 3-91-9.75). No association was found between seroprevalence and age. However, higher prevalence was found among women and was related to duration of exposure to chickens. The concentration of antibodies from a few subjects remained very high after adsorption. Significant differences between the men and women were found for the prevalence of antibodies for ALV but were not related to exposure to chickens.
Journal of Virology, 2007
Marek's disease virus (MDV) is an alphaherpesvirus that induces a highly malignant T-lymphoma in ... more Marek's disease virus (MDV) is an alphaherpesvirus that induces a highly malignant T-lymphoma in chickens. The viral genome encodes two identical copies of a viral telomerase RNA subunit (vTR) that exhibits 88% sequence identity to its chicken ortholog chTR. The minimal telomerase ribonucleoprotein complex consists of a protein subunit with reverse transcriptase activity (TERT) and an RNA subunit (TR). The active complex compensates for the progressive telomere shortening that occurs during mitosis and is involved in the cell immortalization process. We show here that the upregulation of telomerase activity is associated with an increase in vTR gene expression in chickens infected with the highly oncogenic MDV strain RB-1B. A comparative functional analysis of the viral and chicken TR promoters, based on luciferase reporter assays, revealed that the vTR promoter was up to threefold more efficient than the chTR promoter in avian cells. We demonstrated, by directed mutagenesis of the vTR promoter region, that the stronger transcriptional activity of the vTR promoter resulted largely from an E-box located two nucleotides downstream from the transcriptional start site of the vTR gene. Furthermore, transactivation assays and chromatin immunoprecipitation assays demonstrated the involvement of the c-Myc oncoprotein in the transcriptional regulation of vTR. Finally, an Ets binding site was specifically implicated in the transcriptional regulation of vTR in the MDV-transformed lymphoblastoid cell line MSB-1.
Molecular Pathology, 2002
Aims: Lymphoblastoid cell lines derived from Marek's disease virus (MDV) induced tumours have ser... more Aims: Lymphoblastoid cell lines derived from Marek's disease virus (MDV) induced tumours have served as models of MDV latency and transformation. They are stable and can be cultured with no detectable MDV genomic alterations upon repeated passaging. An MDV transformed lymphoblastoid T cell line (T9 cell line) has been reported to contain a disrupted MDV BamHI-H fragment and a Rous associated virus insertional activation of the c-myb protooncogene. In an attempt to define the respective participation of c-myb and MDV in the transformed phenotype of T9 cells, an analysis of MDV oncogenic sequences (BamHI-H, BamHI-A, and EcoQ fragments) was performed in these cells. Methods: Using two different passages of the T9 cell line (late and early passages), the organisation of the MDV oncogenic regions and their expression in these cells were analysed. In vivo assessment of the oncogenicity of the virus contained within these cells was assessed by injecting them into 1 day old chickens. Results: In T9 cells maintained in culture for up to six months (late T9), the MDV ICP4 gene was disrupted, whereas the meq gene was actively transcribed. The alterations of the MDV genome in these cells correlated with the inability of the virus to induce the classic signs of Marek's disease in 1 day old chickens. However, early T9 cells submitted to a limited number of passages induced classic MDV pathogenicity, as efficiently as the MDV control cell line (T5), and did not show gross structural changes in the oncogenic MDV sequences. Conclusions: Although the expression pattern of the MDV oncogenes in early T9 cells was identical to the one reported for other MDV transformed cells, longterm culture of an MDV transformed cell line containing a RAV insertional activation of the c-myb protooncogene led to the disruption of the MDV BamHI-H and BamHI-A oncogenic regions. In the late T9 cells MEQ was the only detected MDV oncoprotein. These results suggest that in the late T9 cells the truncated MYB protein compensates for the loss of MDV oncoproteins and reinforce the possibility that MEQ and MYB cooperate in the maintenance of the transformed state and the tumorigenic potential of these cells.
Journal of Cancer Research and Clinical Oncology, 1995
ABSTRACT Without Abstract
Journal of Biotechnology, 2014
The establishment of the microRNA (miRNA) expression signatures is the basic element to investiga... more The establishment of the microRNA (miRNA) expression signatures is the basic element to investigate the role played by these regulatory molecules in the biology of an organism. Marek's disease virus 1 (MDV-1) is an avian herpesvirus that naturally infects chicken and induces T cells lymphomas. During latency, MDV-1, like other herpesviruses, expresses a limited subset of transcripts. These include three miRNA clusters. Several studies identified the expression of virus and host encoded miRNAs from MDV-1 infected cell cultures and chickens. But a high discrepancy was observed when miRNA cloning frequencies obtained from different cloning and sequencing protocols were compared. Thus, we analyzed the effect of small RNA library preparation and sequencing on the miRNA frequencies obtained from the same RNA samples collected during MDV-1 infection of chicken at different steps of the oncoviral pathogenesis. Qualitative and quantitative variations were found in the data, depending on the strategy used. One of the mature miRNA derived from the latency-associated-transcript (LAT), mdv1-miR-M7-5p, showed the highest variation. Its cloning frequency was 50% of the viral miRNA counts when a small scale sequencing approach was used. Its frequency was 100 times less abundant when determined through the deep sequencing approach. Northern blot analysis showed a better correlation with the miRNA frequencies found by the small scale sequencing approach. By analyzing the cellular miRNA repertoire, we also found a gap between the two sequencing approaches. Collectively, our study indicates that next-generation sequencing data considered alone are limited for assessing the absolute copy number of transcripts. Thus, the quantification of small RNA should be addressed by compiling data obtained by using different techniques such as microarrays, qRT-PCR and NB analysis in support of high throughput sequencing data. These observations should be considered when miRNA variations are studied prior addressing functional studies.
Immunogenetics, 2003
The chicken major histocompatibility complex (MHC) genes are organized into two genetically indep... more The chicken major histocompatibility complex (MHC) genes are organized into two genetically independent clusters which both possess class I and class IIb genes: the classical B complex and the Restriction fragment pattern-Y (Rfp-Y) complex. In this study, we have examined the role of Rfp-Y genes in transplantation immunity. For this we used three sublines, B19H1, B19H2 and B19H3, derived from a line fixed for B19. Southern blots, PCR-SSCP assays using primers specific for Rfp-Y genes, and Rfp-Y class I allele-specific sequencing show that the polymorphisms observed in B19H1, B19H2 and B19H3 are due to the presence of three different Rfp-Y haplotypes. The Rfp-Y class I (YF) alleles in these three haplotypes are highly polymorphic, and RT-PCR shows that at least two YF loci are expressed in each subline. The three sublines show Rfp-Y-directed alloreactivity in that Rfp-Y-incompatible skin grafts are rejected within 15 days, a rate intermediate between that seen in B-incompatible rejection (7 days) and that observed for grafts within the sublines (20 days). We conclude that Rfp-Y has an intermediate role in allograft rejection, likely to be attributable to polymorphism at the class I loci within this region.
Genetics Selection Evolution, 2004
Selection for disease resistance related traits is a tool of choice for evidencing and exploring ... more Selection for disease resistance related traits is a tool of choice for evidencing and exploring genetic variability and studying underlying resistance mechanisms. In this framework, chickens originating from a base population, homozygote for the B 19 major histocompatibility complex (MHC) were divergently selected for either progression or regression of tumors induced at 4 weeks of age by a SR-D strain of Rous sarcoma virus (RSV). The first generation of selection was based on a progeny test and subsequent selections were performed on full-sibs. Data of 18 generations including a total of 2010 birds measured were analyzed for the tumor profile index (TPI), a synthetic criterion of resistance derived from recording the volume of the tumors and mortality. Response to selection and heritability of TPI were estimated using a restricted maximum likelihood method with an animal model. Significant progress was shown in both directions: the lines differing significantly for TPI and mortality becoming null in the "regressor" line. Heritability of TPI was estimated as 0.49 ± 0.05 and 0.53 ± 0.06 within the progressor and regressor lines respectively, and 0.46 ± 0.03 when estimated over lines. Preliminary results showed within the progressor line a possible association between one Rfp-Y type and the growth of tumors.
BMC Cancer, 2010
Background: Telomerase activation, a critical step in cell immortalization and oncogenesis, is pa... more Background: Telomerase activation, a critical step in cell immortalization and oncogenesis, is partly regulated by alternative splicing. In this study, we aimed to use the Marek's disease virus (MDV) T-cell lymphoma model to evaluate TERT regulation by splicing during lymphomagenesis in vivo, from the start point to tumor establishment. Results: We first screened cDNA libraries from the chicken MDV lymphoma-derived MSB-1 T-cell line, which we compared with B (DT40) and hepatocyte (LMH) cell lines. The chTERT splicing pattern was cell line-specific, despite similar high levels of telomerase activity. We identified 27 alternative transcripts of chicken TERT (chTERT). Five were in-frame alternative transcripts without in vitro telomerase activity in the presence of viral or chicken telomerase RNA (vTR or chTR), unlike the full-length transcript. Nineteen of the 22 transcripts with a premature termination codon (PTC) harbored a PTC more than 50 nucleotides upstream from the 3' splice junction, and were therefore predicted targets for nonsense-mediated decay (NMD). The major PTC-containing alternatively spliced form identified in MSB1 (ie10) was targeted to the NMD pathway, as demonstrated by UPF1 silencing. We then studied three splicing events separately, and the balance between in-frame alternative splice variants (d5f and d10f) plus the NMD target i10ec and constitutively spliced chTERT transcripts during lymphomagenesis induced by MDV indicated that basal telomerase activity in normal T cells was associated with a high proportion of in-frame non functional isoforms and a low proportion of constitutively spliced chTERT. Telomerase upregulation depended on an increase in active constitutively spliced chTERT levels and coincided with a switch in alternative splicing from an in-frame variant to NMD-targeted variants. Conclusions: TERT regulation by splicing plays a key role in telomerase upregulation during lymphomagenesis, through the sophisticated control of constitutive and alternative splicing. Using the MDV T-cell lymphoma model, we identified a chTERT splice variant as a new NMD target.
Avian Pathology, 2000
This study was performed to examine the effect of Marek's disease virus (MDV) serotype 1 ... more This study was performed to examine the effect of Marek's disease virus (MDV) serotype 1 vaccine (CVI988/Rispens) on the pathogenicity of Cryptosporidium baileyi , and to determine whether C. baileyi infection could prevent the development of vaccinal Marek's disease (MD) immunity in specific pathogen free (SPF) chickens. Sixty-eight SPF homozygous B13 White Leghorn chickens were divided into seven groups. C. baileyi was orally administered at 5 days of age (day 4) in chickens infected with Rispens vaccine at day 0 or at day 8 and challenged with HPRS-16 strain of oncogenic MDV at day 15. Relevant control groups were constituted. The chickens were kept in isolators until the end of the experiment at day 62. The parameters evaluated were clinical signs, kinetics of oocyst shedding, mortality, macroscopic and microscopic lesions, cryptosporidia location in various organs and serum anti- C. baileyi antibodies at days 42 and 62. Our results show that C. baileyi , which is considered to be non-pathogenic when inoculated orally, may become highly pathogenic. It induced severe mortality and developed in organs other than classical target sites when chickens were vaccinated with Rispens vaccine and challenged with the HPRS-16 strain of MDV.However,parasite infection does not prevent the induction of vaccinal immunity for MD. Our results also show that vaccination of B13 chickens at hatching induces higher protection against challenge with HPRS-16 MDV at day 15 than vaccination at day 8.
Avian Diseases, 1990
Molecular polymorphism of the B complex was studied in serologically defined B19 haplotypes by us... more Molecular polymorphism of the B complex was studied in serologically defined B19 haplotypes by use of class I, class II, and class IV probes in Southern blot experiments in chickens. All chickens studied shared identical class IV restriction patterns. In contrast, class I and class II probes revealed six and five subtypes of B19 haplotype, respectively. These subtypes may be resolved in three homozygous genotypes and their corresponding heterozygous combinations. Previous genetic selection allowed us to distinguish two subpopulations in these B19 chickens with regard to the fate of Rous sarcoma virus (RSV)-induced tumors. Molecular genotyping was applied to B19 chickens challenged with RSV in order to determine whether there is a correlation between one of the molecularly defined subtypes and the progressor/regressor phenotypes of the chickens. None of the molecularly defined subtypes correlated with the progressor or regressor phenotype of the challenged birds.
Avian Diseases, 1999
Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicit... more Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.
Archives of Virology, 1988
superinfected with Rous Sarcoma virus (RSV) synthesis of vsrc mRNA and RSV env mRNA decreases. In... more superinfected with Rous Sarcoma virus (RSV) synthesis of vsrc mRNA and RSV env mRNA decreases. In these cells post-translational processing of RSV precursor proteins is impaired and small amounts of VSV antigens are detected.
Archives of Virology, 2006
We collected paraffin-embedded myelocytomatoses induced by subgroup J avian leukosis virus (ALV-J... more We collected paraffin-embedded myelocytomatoses induced by subgroup J avian leukosis virus (ALV-J) in French poultry from 1992 to 2000. We used nested PCR to obtain the U3 LTR and the E element sequences that encompass putative binding sites for transcription factors. We observed minor mutations in the U3 sequences that rarely affected transcription factor binding sites, thus preserving the transcriptional potential of the U3 LTR. However, we observed a large variability in the E element sequences from both field and experimental tumor samples. This variability involved genomic rearrangements and various deletions that most often occurred between two direct repeat sequences. Moreover, in seven DNA samples of the 22 field tumors analyzed, we observed two different sequences for the E element region, suggesting that proviral genomes of two different sizes may be simultaneously present in a tumor. Even though most of the E element sequences were mutated or rearranged, all myelocytomatosis samples always exhibited one E element sequence containing at least one putative C/EBP binding site that was unaffected and still potentially functional.
Archives of Virology, 2010
Mdv1-miR-M4 is one of 25 microRNAs (miRNAs) expressed by Marek&am... more Mdv1-miR-M4 is one of 25 microRNAs (miRNAs) expressed by Marek's disease virus (MDV-1), an oncogenic alphaherpesvirus that induces fatal T-cell lymphoma in chickens. Mdv1-miR-M4 was shown to be the second functional viral ortholog of miR-155, a cellular miRNA that plays a crucial role in several physiological and pathological processes in lymphocyte biology. In this study, we investigated a panel of putative mdv1-miR-M4 targets involved in gene networks affecting both cellular and viral life cycles. Using luciferase reporter assays, we showed that mdv1-miR-M4-5P and miR-155 efficiently targeted a common set of 3' untranslated regions (3'UTR) of six cellular genes (GPM6B, RREB1, c-Myb, MAP3K7IP2, PU.1 and C/EBP). In addition, we also investigated the interactions between mdv1-miR-M4-5P and mdv1-miR-M43P and viral mRNAs encoding UL28 and UL32 in both reporter and western blot assays. Mdv1-miR-M4 specifically inhibited the translation of these two viral proteins, which are involved in the cleavage/packaging of herpesvirus DNA.
Archives of Virology, 2008
The use of the complete DNA sequence for the Marek's disease virus (MDV) ... more The use of the complete DNA sequence for the Marek's disease virus (MDV) serotype 1 vaccine strain CVI988 Rispens in comparative genomic studies with virulent strains of MDV has revealed the presence of a number of insertions, deletions and single-nucleotide polymorphisms. In this study, we investigated a SNP in the H/ACA box of the viral RNA subunit of telomerase (vTR). We sequenced vTR from four different batches of CVI988 vaccine originating from a single commercial company. The A-to-G mutation defining the SNP in the H/ACA box of CVI988 vTR was present in only some of the batches. Thus, although this mutation affects CVI988 vTR function, it is not shared by all CVI988 isolates and may be a stochastic rather than causative event in CVI988 attenuation.
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Papers by Ginette Dambrine