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M M Pater

Publications and source records attributed to M M Pater.

71 records · Page 4Linked to original sources
PubMed1984

Thymidine kinase of herpes virus as a vehicle for the isolation and characterization of unknown mammalian promoters and enhancers.

We have previously reported that the promoter of the thymidine kinase (TK) gene of herpes virus (HSV) can be replaced with the early promoter of SV40. In the present study we report the construction of a TK- plasmid (TK-pML-BglII) in which the TK promoter has been removed and a new BglII site has been regenerated for the insertion of exogenous promoters in front of this nonexpressed gene. We have tested the feasibility of using this plasmid for the isolation of unknown promoters by inserting DNA fragments containing the early and late promoters of human papovaviruses and have obtained activity. We have also inserted the fragments containing the 72-bp repeat enhancer sequences of SV40 and 107-bp repeat of the human BK virus into the intact TK plasmid (TK-pML) and observe increased frequency of transformation of mouse Ltk- cells to the TK+ phenotype. These results show that the TK system can be used as a vehicle for the isolation of unknown mammalian promoters and/or enhancers.

Animals↗
PubMed1983

Multiple origins of the complementary defective genomes of RF and origin proximal sequences of GS, two human papovavirus isolates.

It has previously been shown that the genome of RF virus, a variant of the human papovavirus, BK, consists of two DNA species, one (R1a) with a deletion corresponding to the early and the other (R2) with a deletion corresponding to the late region of BKV (A. Pater, M.M. Pater, and G. di Mayorca (1980). J. Virol. 36, 480-487; A. Pater, M. M. Pater, R. M. Dougherty, and G. di Mayorca (1981a). Virology 113, 86-94). In this report transfection experiments are used to show that these DNA species are individually defective for infection and that both DNA molecules are required simultaneously for the infection of human embryonic kidney (HEK) cells. DNA fragments containing the origin of replication in each of the DNA species are analyzed to show that R1a contains three and R2 contains two origins of replication. In addition, several changes in the repeat region proximal to the origin of replication are observed. The changes involve deletions and insertions. Examination of the deleted junctions most often reveals involvement of short stretches of repeated sequences (hot spots) in recombination. Another observed change is the insertion into R2 of a 63-bp sequence which contains no homology to either BK or SV40 DNA. This insertion is into the late-promoter region of this late-region coding DNA and appears to replace a poor "TATA" box in BK wild type with a better TATA box with the correct spacing from the "CAAT" box. A 304-bp fragment containing the origin of replication, early and late promoters, and the repeat units proximal to the origin of replication of GS, another variant of human BKV papovaviruses has also been sequenced. Several rearrangements, including deletions and insertions in the repeat region, are observed. Moreover, when homologous regions of this virus are compared to that of BKV, five base changes are detected, one of which is in the 23-bp origin region. This base change gives this 23-bp palindrome of GS a perfect two-fold rotational symmetry.

Cell Line↗
PubMed1983

Positive control of the herpes simplex virus thymidine kinase gene requires upstream DNA sequences.

We examined the ability of deleted versions of the herpes simplex virus type 1 thymidine kinase gene, present in biochemically transformed mouse cells, to be induced in trans to a higher level of expression by superinfecting herpes simplex virus immediate early gene products. The results demonstrate that sequences mapping between -200 and -80 and between -70 and -12 are required for induction. As these regions are largely coincident with the previously identified thymidine kinase gene promoter, the results suggest that herpes simplex virus immediate early gene products or their metabolic product activate thymidine kinase expression by acting at the promoter region to increase the rate of transcription.

Base Sequence↗
PubMed1982

BK virus-transformed inbred hamster brain cells: status of viral DNA in subclones.

We have recently reported that viral DNA sequences in inbred LSH hamster brain cells transformed by the GS variant of BK virus (LSH-BR-BK) are present predominantly in a free form (Beth et al., J. Virol. 40:276-284, 1981). In this report, we confirm that the presence of viral DNA sequences in these cells is not due to virus production, since viral capsid proteins were not detected by immunoprecipitation. Furthermore, we examined the status of viral DNA in 15 subclones of this cell line and detected free and integrated viral DNA sequences in only 5 of the subclones. The other 10 subclones contained exclusively integrated viral DNA sequences, as shown by the blot hybridization of high-molecular-weight cell DNA which was uncleaved or digested with HincII, for which there are no sites in viral DNA. The arrangement of viral DNA in these clones was further analyzed by cleavage of cellular DNA with HpaII and HindIII. Mitomycin (0.03 microgram/ml) treatment of subclones containing only integrated sequences resulted in the appearance of free viral DNA sequences in some of these cells. This result supports the postulation that free viral DNA in LSH-BR-BK cells is made up of excision products of observed tandemly repeated integrated sequences. In addition to the large T- and small t-antigens, LSH-BR-BK and all of its 15 subclones contained two antigen species which were larger than large T and one species which was smaller than small t. The number of tumor antigens in the LSH- BR-BK cell line and its subclones with a large copy number in a free form was not more than in the subclones with low copy number and integrated DNA. This suggests that free viral DNA is not a template for tumor antigen production in transformed cells.

Animals↗
PubMed1981

Genome analysis of MG virus, a human papovavirus.

The genome of MG virus, a variant of the human papovavirus BK virus, consists of two molecules, M1 and M2, M1 and M2 have deletions which correspond to 0.33 to 0.55 map unit and 0.77 to 0.85 map unit, respectively, from the EcoRI site on the BK virus genome. Restriction enzyme analysis of the DNAs of these viruses revealed many alterations in both DNA species. Both M1 and M2 DNAs have three recognition sites for EcoRI. M1 has a single recognition site for HindIII and five sites for PvuII. M2 has a single recognition site for PuvII and three sites for HindIII. The sites of these and several other restriction enzymes on each DNA molecule were mapped after the cloning of M1 and M2 DNAs into pBR322 at their unique HindIII and PvuII sites, respectively.

BK Virus↗
PubMed1981

BK virus-transformed inbred hamster brain cells. I. Status of the viral DNA and the association of BK virus early antigens with purified plasma membranes.

Inbred LSH hamster brain cells were transformed in vitro by the GS strain of BK virus (BKV), and transplantable tumors classified as undifferentiated glioblastomas were induced in the syngeneic host. The viral status in the transformed cells, designated LSH-BR-BK, was established. About 46 genome equivalents per cell of viral DNA was detected, with the majority of sequences in a free form. The transformed cells expressed large quantities of tumor (T) antigen as well as surface (S) antigen as demonstrated by indirect immunofluorescence. Sixty-three percent of tumor-bearing hamsters produced high-titer antibodies against T, whereas 3 of 14 (21%) hamsters also produced antibodies against the BKV-specific S antigen. Furthermore, the relatedness of BKV early gene products, including T, S, and tumor-specific transplantation antigen, was established by the production of a rabbit antiserum against highly purified plasma membranes of LSH-BR-BK cells and by the induction of a BKV-specific tumor-specific transplantation antigen response by these plasma membranes in the syngeneic host.

Animals↗
PubMed1980

Arrangement of the genome of the human papovavirus RF virus.

DNA from plaque-purified RF virus, a variant of BK virus, was found to contain two species of molecules. Hybridization of each DNA species to the fragments of BK virus DNA revealed that one species had a deletion corresponding to at least 50% of the late region and the other had a deletion corresponding to at least 40% of the early region of BK virus DNA. Analysis by cleavage of each RF virus DNA species with restriction endonucleases EcoRI, HindIII, AvaII, and PvuII, when compared with BK virus DNA, revealed that the size and number of fragments were different. These results suggest the loss of some restriction sites and the appearance of new sites, probably as a result of base changes in each RF virus DNA species. Furthermore, analysis of the restriction map of each DNA molecule revealed in insertion(s) in both DNA species.

BK Virus↗
PubMed1979

Comparative analysis of GS and BK virus genomes.

Analysis of heteroduplexing between the genomes of GS virus, a BK-group virus, and the prototype BK virus revealed one region of nonhomology. Further analysis by cleavage of viral DNA with the restriction endonucleases EcoRI, HindIII, and HaeIII revealed that base changes in the GS virus genome spanned 0.6 to 0.7 map unit from the EcoRI site. Large T and small t antigens of GS virus appear to be similar in size to the BK virus antigens.

Antigens, Neoplasm↗
PubMedDate not supplied

Isolation and characterization of papillomavirus DNA from nasal inverting (schneiderian) papillomas.

To elucidate the possible role of papillomaviruses as etiological agents in nasal inverting papillomas, DNA hybridization techniques were used. Total DNA from two nasal inverting papillomas was examined for the presence of DNA from human papillomavirus (HPV) types 6 and 11 under stringent conditions of hybridization. Both lesions contained DNA hybridizing with HPV 11. Restriction enzyme digestion and subsequent Southern blotting of the DNA samples revealed that one lesion contained viral DNA identical to HPV 11a. The DNA of the other lesion contained an extra 500 base pair insertion. These results provide definitive evidence for the first time for the association of HPV with nasal inverting papillomas.

Adolescent↗