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R Rochford

Publications and source records attributed to R Rochford.

25 records · Page 2Linked to original sources
PubMed1991

Relationship between polyadenylated and nonpolyadenylated herpes simplex virus type 1 latency-associated transcripts.

RNA from the region of the genome encoding herpes simplex virus type 1 latency-associated transcripts (LATs) expressed during lytic infection yields low abundances of both polyadenylated and nonpolyadenylated forms. As has been previously shown for latent infection (A. T. Dobson, F. Sedarati, G. Devi-Rao, W. M. Flanagan, M. J. Farrell, J. G. Stevens, E. K. Wagner, and L. T. Feldman. J. Virol. 63:3844-3851, 1989), all lytic-phase expression of such transcripts requires promoter elements situated approximately 600 bases 5' of the previously mapped 5' end of the poly(A)- forms of LAT. Transient expression experiments revealed no other clear promoter elements within this region, and relatively small amounts of latent-phase transcripts initiating at the same site as observed for lytic-phase LAT could be detected by RNase protection assays. In the lytic phase of infection, the most abundant forms of polyadenylated LAT extended 1,600 bases from the initiation site near the LAT promoter to a potential splice donor site. Poly(A)- LAT species were not recovered in significant amounts from lytically infected neuroblastoma cells, but such RNA from lytically infected rabbit skin cells comapped with poly(A)- LAT from latently infected sensory neurons. Both map between canonical 5' splice donor and 3' splice acceptor site 1,950 bases apart. Poly(A)- LAT cochromatographed with uncapped rRNA on m-aminophenyl boronate agarose under conditions in which capped mRNA was bound. All of these data confirm the previously presented scheme for the expression of poly(A)- LAT as a stable intron derived from the splicing of a large primary transcript; however, we were unable to detect the spliced polyadenylated product of this splicing reaction.

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PubMed1990

Genetic analysis of the enhancer requirements for polyomavirus DNA replication in mice.

In this report, we describe the first systematic analysis of the genetic requirements for polyomavirus (Py) enhancer-activated viral DNA replication during the acute phase of infection in mice. Four mutants were made which substituted XhoI sites for conserved enhancer consensus sequences (adenovirus type 5 E1A, c-fos, simian virus 40, and a glucocorticoidlike consensus sequence). Viral DNA replication in infected mouse organs was measured by DNA blot analysis. Only the loss of the glucocorticoidlike consensus sequence element significantly reduced Py DNA replication in the kidneys, the primary target organ for viral replication. The loss of the c-fos, adenovirus type 5 E1A, or simian virus 40 consensus sequences, however, expanded organ-specific viral DNA replication, relative to wild-type Py, by allowing high-level replication in the pancreas or heart or both. Analysis of Py variants selected for replication in undifferentiated embryonal carcinoma cell lines (PyF441, PyF111) showed that there was little change in levels of viral DNA replication in kidneys and other organs as compared with those in the wild-type virus. If the entire B enhancer is deleted, only low overall levels of viral replication are observed. Wild-type levels of replication in the kidneys can be reconstituted by addition of a single domain from within the A enhancer (nucleotides 5094 to 5132) to the B enhancer deletion virus, suggesting that a single domain from the A enhancer can functionally substitute for the entire B enhancer. This also indicates that the determinants for kidney-specific replication are not found in the B enhancer.

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PubMed1990

Minimal subenhancer requirements for high-level polyomavirus DNA replication: a cell-specific synergy of PEA3 and PEA1 sites.

The cell-specific regulation of DNA replication has important implications for the molecular strategy of cellular gene control. Mouse polyomavirus (Py) DNA replication is examined as a model of cell-specific replication control. Using an FM3A-derived mouse cell line which expresses early viral proteins (FOP cells), we determined the minimal sequence requirements for viral DNA replication. FOP cells were observed to have much simpler enhancer requirements than 3T6 and many other cells and did not need a B enhancer for high levels of DNA replication. Using these cells, we show that the individual or tandem binding sites for several unrelated trans-acting factors which are generally subfunctional as transcriptional enhancers (simian virus 40 A core, TGTGGAATG; EBP20, TGTGGTTTT; PEA1 [an AP-1 analog], GTGACTAA; PEA2, GACCGCAG; and PEA3, AGGAAG) stimulated low levels of Py DNA replication. The ordered dimeric combination of PEA3 and PEA1 factor-binding sites, however, acted synergistically to stimulate viral DNA replication to high wild-type levels. This is in contrast to prior results in which much larger enhancer sequences were necessary for high-level viral DNA replication. PEA3/PEA1-stimulated DNA replication showed a distance and orientation independence relative to the origin, which disagrees with some but not other prior analyses of enhancer-dependent DNA replication. It therefore appears that trans-acting factor-binding sites (enhansons) can generally activate DNA replication and that the AP-1 family of sites may act synergistically with other associated trans-acting factors to strongly affect Py DNA replication in specific cells.

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PubMed1987

A pancreas specificity results from the combination of polyomavirus and Moloney murine leukemia virus enhancer.

An infectious recombinant polyomavirus was constructed in which a regulatory region of its genome, the B enhancer region (nucleotides 5128-5265) has been replaced with the 72- or 73-base-pair repeat enhancer from the Moloney murine leukemia virus genome. We show that this recombinant polyomavirus displays a strong tissue specificity for the pancreas of mice. This organ was not permissive for either the parental polyomavirus, which is predominantly kidney and salivary gland specific, or the Moloney murine leukemia virus, which is lymphotropic. This result indicated that tissue specificity can be achieved by a combination of apparently modular elements. Some of the implications of a modular mechanism of tissue specificity are considered.

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PubMed1985

Developmental expression of rat transforming growth factor-alpha mRNA.

Expression of the gene encoding transforming growth factor-alpha (TGF alpha) was examined in developing rat embryos by using a cloned TGF alpha cDNA as a hybridization probe. Northern blot analysis of RNA isolated from whole fetuses revealed that TGF alpha mRNA was present at relatively high levels in 8- through 10-day-old embryos and then declined to the low or undetectable level, which is characteristic of adult tissues before birth. The level of TGF alpha mRNA present during early gestation was similar to that present in retrovirus-transformed cells in culture, suggesting that TGF alpha expression is not highly localized in the embryo. These observations are consistent with the hypothesis that TGF alpha plays a role in development, possibly as a fetal growth factor.

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PubMedDate not supplied

Gammaherpesvirus-induced lung pathology is altered in the absence of macrophages.

The purpose of this study was to examine the lung pathogenesis of murine gammaherpesvirus (MHV-68) infection in mice that lack CC chemokine receptor CCR2, an important receptor for macrophage recruitment to sites of inflammation. BALB/c and CCR2(-/-) mice were inoculated intranasally (i.n.) with MHV-68 and samples were collected during acute infection (6 dpi) and following viral clearance (12 dpi). Immunohistochemistry was used to determine which cells types responded to MHV-68 infection in the lungs. Lung pathology in infected BALB/c mice was characterized by a mixed inflammatory cell infiltrate, necrosis, and increased alveolar macrophages by 12 dpi. Immunohistochemistry showed intense positive staining for macrophages. CCR2(-/-) mice showed greater inflammation in the lungs at 12 dpi than did BALB/c mice, with more necrosis and diffuse neutrophil infiltrates in the alveoli. Immunohistochemistry demonstrated much less macrophage infiltration in the CCR2(-/-) mice than in the BALB/c mice. These studies show that CCR2 is involved in macrophage recruitment in response to MHV-68 infection and illustrates how impairments in macrophage function affect the normal inflammatory response to this viral infection.

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