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M Nonoyama

Publications and source records attributed to M Nonoyama.

At least 91 records · Page 5Linked to original sources
PubMed1990

Suppression of mouse mammary tumor proviral DNA and protooncogene expression: association with nutritional regulation of mammary tumor development.

Chronic energy intake restriction (CEIR) reduces mouse mammary tumor virus (MMTV)-induced mammary tumors in C3H/Ou mice. Fewer than 10% of C3H/Ou mice developed mammary tumors during 88 wk of study when subjected to CEIR regardless of calorie source (fat vs. carbohydrate). By contrast, 100% of mice fed ad libitum diets relatively high in fat or carbohydrate or a commercial diet developed tumors by 35-40 wk. MMTV proviral DNA transcription was shown to be activated in spleen, liver, lung, kidney, small intestine, and mammary gland of mice consuming these diets ad libitum. By contrast, these messages were suppressed by CEIR in all tissues analyzed except spleen. MMTV proviral messages in liver and mammary gland increased with age in full-fed mice and were suppressed by CEIR. These findings suggest that the nutritional regulation of MMTV proviral DNA expression is tissue-specific. In CEIR mice the suppressed MMTV proviral DNA transcripts in mammary gland and liver increased with time in association with the delayed onset of mammary tumors. Mammary tumorigenesis in C3H mice is associated with integration of MMTV proviral DNA, which appears to activate a putative mammary tumor protooncogene, int-1. CEIR apparently decreases the frequency of viral reintegration adjacent to the int-1 gene and thus inhibits expression of int-1 and probably an initiation step in mammary tumorigenesis. Expression of other putative protooncogenes, int-2 and ras, in liver tissue was also reduced by CEIR. These findings indicate that both initiation and promotion of mammary tumorigenesis are influenced by CEIR in C3H/Ou mice.

Animals↗
PubMed1990

Modification of human immunodeficiency viral replication by pine cone extracts.

We have shown previously that two fractions (PC6 and PC7) extracted from cones of the Japanese white pine Pinus parvifloria Sieb. et Zucc have potent immunopotentiating effects. Here, we show that PC6 and PC7 inhibited HIV-1 replication (greater than 95%), in a dose-dependent manner, in chronically infected CR10/HIV-1 cells and in acute cytolytic HIV-1 infection of CEM cells. Treatment of CEM cells, prior to or after acute infection with HIV-1, reduced subsequent viral production, but the best inhibitory effect was obtained with treatment before and after infection: an 80% inhibition was achieved with as little as 3 micrograms/ml of PC6. Comparable results were also obtained when PC6 was used to inhibit HIV-1 replication in the U937 human histiocytic lymphoma cell line. Both PC6 and PC7 were relatively nontoxic to cells. The anti-HIV-1 effect of PC6 and PC7 we observed in this report, coupled with earlier reports of their immunopotentiating properties suggest their potential as ideal therapeutic agents for the treatment of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Latent transcripts of Marek's disease virus are clustered in the short and long repeat regions.

Marek's disease herpesvirus (MDV) induces tumors in chickens, and lymphoblastoid cells derived from such tumors contain the viral genome in a latent state and do not produce infectious virus. Poly(A)+ RNAs extracted from MDV-induced kidney lymphoma cells and from MKT-1 cells, a nonproducing lymphoblastoid cell line derived from a tumor induced by MDV, were electrophoretically separated under denaturing conditions, transferred to a solid substrate, and hybridized with labeled DNA probes representing approximately 95% of the virus genome. These analyses revealed 29 viral RNA transcripts in the kidney lymphoma and 32 viral RNAs in MKT-1 cells. In both instances, the transcripts hybridized to a restricted region comprising approximately 20% of the MDV genome located in the repeats flanking the long and short unique sequences and in the adjacent unique sequences. The sizes of the transcripts derived from kidney lymphoma and MKT-1 cells and the distributions of the homologous regions in the viral genome were very similar. The most abundant transcripts were homologous to the BamHI I2 fragment. The results suggest that expression of the MDV genome in MKT-1 cells closely reflects the expression of the MDV genome in tumors. The gene expression over extended regions of the genome is in concordance with that observed in latent gammaherpesviruses rather than that observed in latent alphaherpesviruses.

Cell Line↗
PubMed1989

Cycloheximide-resistant gene of Epstein-Barr virus in freshly infected B lymphocytes.

The transcription of latent Epstein-Barr viral (EBV) genes, i.e., genes encoding EBNA-1, EBNA-2, EBNA-3A, -3B, -3C, and LMP, were detected in human tonsillar lymphocytes early after infection with EBV. Transcription of the BHLF-1 open reading frame was also detected at this initial phase of immortalization. Cycloheximide treatment inhibited the transcription of all the latent EBV genes but not BHLF-1. These results suggest that BHLF-1 might be considered an immediate-early gene of EBV. Cycloheximide treatment of EBV-infected cells reduced not only the degree of the transcription but also the size of the transcript for EBNA-2. We hypothesize that the immediate-early expression of BHLF-1 may be required for the enhanced transcription of the viral genes in lymphocytes early after infection with EBV.

Antigens, Viral↗
PubMed1989

Expression of EBNA-3 family in fresh B lymphocytes infected with Epstein-Barr virus.

Four transcripts belonging to the EBNA-3 family were detected during immortalization of human tonsillar lymphocytes with the Epstein-Barr virus. These four transcripts were also detected in immortalized B-lymphoblastoid cells (LCL) and the Burkitt's lymphoma cell line, Namalwa. A 5.0-kb transcript hybridized with the EBNA-3A probe; a 8.5-kb transcript hybridized with the EBNA-3B and -3C probes; and a 5.6- and a 3.6-kb transcript hybridized with the EBNA-3C probe. Sequencing and cDNA analysis showed that the EBNA-3C transcripts contained exons of the most rightward BamHI-E open reading frames, BERF-3 and BERF-4. Moreover, sequencing of cDNA clones revealed exons in the 5' portion homologous to regions in EBV BamHI-C, -W, and -U. Hybridization experiments with EBV BamHI-W and -U probes identified the 8.5- and 5.6-kb transcripts but not the 3.6-kb transcript in LCL. Organization of these transcripts from the EBNA-3 family is discussed.

Antigens, Viral↗
PubMed1989

Loss of Marek's disease virus tumorigenicity is associated with truncation of RNAs transcribed within BamHI-H.

The attenuation of Marek's disease virus (MDV) is associated with loss of pathogenicity and tumorigenicity. Previous studies have demonstrated a strong correlation between attenuation and amplification of a specific sequence located within the MDV terminal and internal repeats. We recently reported that the regions containing the amplified sequences, the BamHI D and H fragments, were transcriptionally active. However, differential transcription activity was observed to exist between attenuated and pathogenic MDV strains. Specifically, a major transcript of 1.8 kilobases was found to be produced by pathogenic MDV and not by attenuated MDV. We now report that the disappearance of this transcript is concomitant with the production of a 0.4-kilobase RNA, an RNA resulting from the truncation of the tumorigenicity-related transcript.

Animals↗
PubMed1989

Structure of the Marek's disease virus BamHI-H gene family: genes of putative importance for tumor induction.

The BamHI H fragment of Marek's disease virus (MDV), which has been hypothesized to contain a tumor-inducing gene, was partially sequenced and analyzed for transcriptional activity. Transcription of several RNAs was found to initiate within BamHI-H, with the major transcripts initiating on either side of a putative MDV origin of lytic replication. A 1.8-kilobase gene family found to be produced only by pathogenic MDV was detected, and its transcription map was produced. It is hypothesized that the 1.8-kilobase gene family is directly associated with the tumorigenic potential of MDV.

Animals↗
PubMed1989

Induction of anti-EBNA-1 protein by 12-O-tetradecanoylphorbol-13-acetate treatment of human lymphoblastoid cells.

Binding of the Epstein-Barr virus (EBV) nuclear antigen (EBNA-1) to BamHI-C DNA was studied by affinity column chromatography followed by immunoblotting with human serum specific for EBNA-1. Two species of EBNA-1 (68 and 70 kilodaltons) were identified in nuclear extracts of the EBV-positive Burkitt's lymphoma cell line Raji and not in nuclear extracts of the EBV-negative Burkitt's lymphoma cell line BJAB. Both EBNA-1s bound specifically to the region required for EBV plasmid DNA maintenance (oriP) located in the BamHI-C fragment. Upon treatment with 12-O-tetradecanoylphorbol-13-acetate, which activates latent EBV genome in Raji cells, the 68-kilodalton EBNA-1 was uncoupled from binding to EBV oriP. Nuclear extracts from 12-O-tetradecanoylphorbol-13-acetate-treated BJAB cells also uncoupled the binding of both EBNA-1s to oriP. DNA-cellulose column chromatography identified two protein species which competed for and uncoupled the binding of EBNA-1 to oriP. The two cellular competitors we called anti-EBNA-1 proteins had molecular masses of 60 and 40 kilodaltons, respectively. They were not found in nuclear extracts of BJAB cells not activated by 12-O-tetradecanoylphorbol-13-acetate.

Antigens, Viral↗
PubMed1988

A novel EBNA-1 titration method and putative anti-EBNA-1 protein.

A novel and rapid EBNA-1 titration method has been developed which uses immunoprecipitation of specific DNA-protein complexes with EBNA-1-positive serum. The method is more sensitive than the conventional immunofluorescence method and has potential value as a diagnostic reagent for clinical laboratories. TPA induction of putative anti-EBNA-1 protein of cellular origin is discussed, which may play a key role for the shift from latent to lytic replication of EBV.

Antibodies, Viral↗
PubMed1988

The structure of Marek's disease virus DNA: amplification of repeat sequence in IRs and TRs.

The structure of Marek's disease virus (MDV) DNA was investigated by using Southern blot hybridization analysis. A heterogeneous region was observed in the inverted repeats region, IRs and TRs, as well as in the TRL and IRL. The results of DNA sequencing of the heterogeneous region showed that the heterogeneity of IRS and TRS was due to amplification of a 178-bp repeat sequence. Amplification of IRS and TRS was found in viral DNA from both pathogenic and nonpathogenic strains. The structure of DNA from the latent MDV genome present in established lymphoblastic cells was also determined. Amplification of the 132-bp repeat sequence in IRL and TRL was not found in latent MDV DNA of established lymphoblastic cells, whereas amplification of the 178-bp repeat sequence in IRS and TRS was found in the same DNA.

Base Sequence↗
PubMed1988

Identification of Marek's disease virus nuclear antigen in latently infected lymphoblastoid cells.

A new Marek's disease virus (MDV) nuclear antigen (MDNA) was identified in two MDV-transformed T-lymphoblastoid cell lines, MKT-1 and MSB-1, derived from chickens bearing tumors induced by MDV. This MDNA was not detected in MSB-1 cells maintained in iododeoxyuridine, which activates the latent MDV genome. Moreover, it was not found in chicken embryo fibroblasts undergoing productive and cytolytic infection with MDV. Expression of MDNA is not related to strain pathogenicity in chickens, because chicken embryo fibroblasts productively infected with the pathogenic RBIB strain or the nonpathogenic CV-1 strain of MDV did not express this antigen. DNA-protein immunoprecipitation studies revealed that MDNA bound to two sites in the 190,00-base-pair (bp) MDV genome. One of these loci identified by MDNA obtained from MKT-1 and MSB-1 cells corresponded to a 476-bp segment within the short unique region of BamHI-A MDV DNA. A second locus located in a 280-bp segment within the short inverted repeat region of BamHI-A was also identified by MDNA from MSB-1 cells but not by MDNA obtained from MKT-1 cells. Analyses of the nucleotide sequence by DNase digestion showed that MDNA protected a 60-bp segment spanning a 22-bp palindromic sequence of the short unique region and a 103-bp sequence encompassing a 32-bp palindrome in the short inverted repeat region of BamHI-A MDV DNA.

Animals↗
PubMed1988

A repeat sequence, GGGTTA, is shared by DNA of human herpesvirus 6 and Marek's disease virus.

Some regions of the genomes of human B-lymphotrophic virus (HBLV), also designated as human herpesvirus 6, and Marek's disease virus were found to hybridize to each other under moderate to stringent conditions, scoring from 10 to 30% base-pair mismatch. Nucleotide sequence analysis showed that a 6-base-pair repetitive sequence, GGGTTA (DR2), present in the IRS-IRL junction region of the Marek's disease virus genome, was also reiterated in the HBLV genome. The function(s) of such a sequence is unknown, but this is the first report of homology between HBLV and a nonhuman herpesvirus.

Animals↗
PubMed1987

Development of cell systems to study viral gene transcription at the initial phase of Epstein-Barr virus infection.

Two infection systems have been introduced in order to study viral gene expression at the initial period of Epstein-Barr virus (EBV) infection which leads to immortalization. The data indicate that major viral gene expression in tonsil lymphocytes at 2 days post-infection (p.i.) with EBV is very similar to that observed in latently infected cells. Both tonsil lymphocyte and BJAB cell (lymphoblastoid cells free of EBV genome) infection with EBV induced similar viral gene transcription. Twelve cDNA clones were prepared from poly(A) RNA of tonsil lymphocytes infected with EBV 2 days p.i. by hybridization with BamHI fragments of EBV DNA. Some cDNAs were derived from primary transcripts of the BamHI-WYHK region, suggestive of splicing of a large transcript. It is possible that a number of cDNA clones may be derived from cellular genes. The derivation of these cDNA clones is being studied.

Bacteriophage lambda↗
PubMed1987

Restriction enzyme map of herpesvirus of turkey DNA and its collinear relationship with Marek's disease virus DNA.

The genome of herpesvirus of turkey (HVT) was shown to consist of long and short unique regions flanked by inverted repeats (J. Cebrian, Kaschka-Dietrich, C., Berthelot, N., and Sheldrick, P., 1982, Proc. Natl. Acad. Sci. USA 79, 555-558). In this paper we report the construction of the linkage map of HVT DNA for BamHI, HindIII, and PstI restriction endonucleases. The maps were constructed by hybridization of 19 cloned BamHI fragments of HVT DNA to electrophoretically separated digests of genomic DNA. Our results indicate that the terminal and internal inverted repeats (TRL and IRL) flanking the long unique sequences (UL) are spanned by BamHI-F fragment and a -F-related terminal fragment, respectively, whereas the terminal and internal inverted repeats (TRS and IRS) flanking the short unique sequences (US) are mostly contained in BamHI-A fragment. Both BamHI-A and -F showed a heterogeneity in size, suggesting the presence of amplification of certain sequences in the inverted repeats. We also report that the HVT genome is collinear with the genetically related Marek's disease virus (MDV) genome, as determined by hybridization of labeled cloned HVT DNA fragments with electrophoretically separated MDV DNA fragments.

Animals↗
PubMed1986

Mapping of genes in BamHI fragment M of Epstein-Barr virus DNA that may determine the fate of viral infection.

We used nuclease digestion to map RNA transcripts encoded in the BamHI M fragment of the Epstein-Barr virus (EBV) genome (strain B95-8). Of the five RNAs, three are rightwardly transcribed, have different cap sites but common 3' termini, and are unspliced. The two remaining RNAs are leftwardly transcribed and are 5' and 3' coterminal. One of these transcripts is spliced, resulting in the removal of a small intron from the 5' region of this RNA. We have previously published data which indicated that the BamHI M region is the first actively transcribed region of the viral genome during the replicative cycle, suggesting that one or more genes in this region is important in the initiation of EBV replication. We have now mapped two large EcoRI restriction fragments which span approximately 75% of the P3HR-1 defective genome and which contain DNA from the BamHI M region of the standard genome. The data indicate that only the coding and 5' flanking sequences for the leftwardly transcribed RNAs are intact within the defective genome. Fewer than 500 bases coding for the 3'-most regions of the rightwardly transcribed RNAs are intact, and it is unlikely that these encode functional native polypeptides. Therefore, it seems that transcriptional activation of the BamHI M-region genes is not mediated directly by the rearrangement of M genes in defective P3HR-1 EBV.

Base Sequence↗
PubMed1986

Process of immortalization by Epstein-Barr virus and oncogenic conversion of the immortalized cells.

Transcription of Epstein Barr virus (EBV) genome during immortalization of tonsil lymphocytes was studied. Cytoplasmic poly(A) RNA was Northern blot hybridized with 32P-labeled cloned EBV fragments. A 5.1 kb band was detected by hybridization with BamHI-H, -F, -K, -A and het fragments. The implication of this finding is discussed. DNA obtained from cells established from a colony of immortalized tonsil lymphocytes in 0.4% soft agar was found to transform NIH 3T3 cells. The transformed cells were able to induce tumor in nude mice, although the originally established lymphocytes from the colony did not. This may indicate that a certain population of EBV immortalized cells may contain a potentially oncogenic gene which can function as an oncogene in NIH 3T3 cells.

Animals↗