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Biomedical subjects

E Prentice

Publications and source records attributed to E Prentice.

10 recordsLinked to original sources
PubMed2001

Mouse hepatitis virus replicase protein complexes are translocated to sites of M protein accumulation in the ERGIC at late times of infection.

The coronavirus mouse hepatitis virus (MHV) directs the synthesis of viral RNA on discrete membranous complexes that are distributed throughout the cell cytoplasm. These putative replication complexes are composed of intimately associated but biochemically distinct membrane populations, each of which contains proteins processed from the replicase (gene 1) polyprotein. Specifically, one membrane population contains the gene 1 proteins p65 and p1a-22, while the other contains the gene 1 proteins p28 and helicase, as well as the structural nucleocapsid (N) protein and newly synthesized viral RNA. In this study, immunofluorescence confocal microscopy was used to define the relationship of the membrane populations comprising the putative replication complexes at different times of infection in MHV-A59-infected delayed brain tumor cells. At 5.5 h postinfection (p.i.) the membranes containing N and helicase colocalized with the membranes containing p1a-22/p65 at foci distinct from sites of M accumulation. By 8 to 12 h p.i., however, the membranes containing helicase and N had a predominantly perinuclear distribution and colocalized with M. In contrast, the p1a-22/p65-containing membranes retained a peripheral, punctate distribution at all times of infection and did not colocalize with M. By late times of infection, helicase, N, and M each also colocalized with ERGIC p53, a specific marker for the endoplasmic reticulum-Golgi-intermediate compartment. These data demonstrated that the putative replication complexes separated into component membranes that relocalized during the course of infection. These results suggest that the membrane populations within the MHV replication complex serve distinct functions both in RNA synthesis and in delivery of replication products to sites of virus assembly.

Animals↗
PubMed2001

The cell biology of coronavirus infection.

The ability to obtain entire volume data on infected cells will allow us to define much more accurately the interactions of viral proteins with host cell structures such as ER, Golgi, and cytoskeletal elements. In addition, the demonstrated ability to express viral proteins fused to fluorescent markers in in live cells will allow us to follow specific proteins or complexes during the course of infection and to determine if exogenously expressed proteins are able to target to sites of active viral replication. This in turn will allow new approaches to the study of viral and cellular protein-protein interactions, as methods to study the biology and pathogenesis of MHV infection at a cellular level. Finally, the approaches described here will allow us to define protein complementation of defective viruses at a cellular level, rather than being dependent on population measurements of RNA, protein, or progeny virus. By combining these approaches with available biochemical and molecular biological approaches and the emerging reverse genetic and recombinant genetic approaches, rapid progress in understanding the details of coronavirus-cell interactions should be possible.

Animals↗
PubMed1999

The putative helicase of the coronavirus mouse hepatitis virus is processed from the replicase gene polyprotein and localizes in complexes that are active in viral RNA synthesis.

The coronavirus mouse hepatitis virus (MHV) translates its replicase gene (gene 1) into two co-amino-terminal polyproteins, polyprotein 1a and polyprotein 1ab. The gene 1 polyproteins are processed by viral proteinases to yield at least 15 mature products, including a putative RNA helicase from polyprotein 1ab that is presumed to be involved in viral RNA synthesis. Antibodies directed against polypeptides encoded by open reading frame 1b were used to characterize the expression and processing of the MHV helicase and to define the relationship of helicase to the viral nucleocapsid protein (N) and to sites of viral RNA synthesis in MHV-infected cells. The antihelicase antibodies detected a 67-kDa protein in MHV-infected cells that was translated and processed throughout the virus life cycle. Processing of the 67-kDa helicase from polyprotein 1ab was abolished by E64d, a known inhibitor of the MHV 3C-like proteinase. When infected cells were probed for helicase by immunofluorescence laser confocal microscopy, the protein was detected in patterns that varied from punctate perinuclear complexes to large structures that occupied much of the cell cytoplasm. Dual-labeling studies of infected cells for helicase and bromo-UTP-labeled RNA demonstrated that the vast majority of helicase-containing complexes were active in viral RNA synthesis. Dual-labeling studies for helicase and the MHV N protein showed that the two proteins almost completely colocalized, indicating that N was associated with the helicase-containing complexes. This study demonstrates that the putative RNA helicase is closely associated with MHV RNA synthesis and suggests that complexes containing helicase, N, and new viral RNA are the viral replication complexes.

Amino Acid Sequence↗
PubMed1988

Prior ethical review of animal versus human subjects research.

During the last decade the animal rights movement has garnered widespread support that now threatens the existence of animal research. Current public sentiment demands researcher accountability and documentation of the potential value of animal research that was largely assumed in the past. One way this can be accomplished is through prior review and approval of animal research protocols by the federally mandated institutional animal care and use committee (IACUC). IACUCs, however, face more difficulty in arriving at consistent and ethically correct decisions than human subject review committees or institutional review boards (IRBs). This article explains why and draws a comparison between animal and human subjects review.

Animal Care Committees↗
PubMed1970

Renin and acute renal failure: studies in man.

Plasma renin concentration was increased, usually appreciably, in 22 out of 25 patients with acute renal failure, the average value being 226 units/litre (mean for normal subjects 8.2 units/1.). The highest renin values were found in the first 10 days of the disease; lower and sometimes normal values were found subsequently. Unequivocal acute tubular necrosis was present in only two of the eight cases examined post mortem.These findings are compatible with Goormaghtigh's proposal that an excess of renin and angiotensin may act within the kidney to produce acute renal failure.

Acute Kidney Injury↗