The Murine Pneumotropic Virus (MPtV), contrary to MurinePolyomavirus (MPyV), seems to be non-tumourigenic in its natural host. Rather, MPtV leads to severe pneumonia and it can also function as a model in research of polyomavirus-induced sickness. When we tested it initially, MPtV large T-antigen (LT) was expressed in a heterologous system. LT was categorized with respect to its metabolic stability and cell immortalizing activity and, after refinement, to its particular DNA binding. The lack of permissive cell culture system for MPtV has hindered its research. We tried to broaden the host variety of the virus by altering the regulatory and late regions of the genome. We used the enhancer substitution mutant (KVm1), It features a transcriptional enhancer replaced with a related DNA segment from MPyV. It managed to replicate in mouse 3T3 cells and form virus particles which were infectious in mice. However, effective infection of cells in vitro wasn’t achieved using this mutant virus, perhaps because of the lack of virus-specific receptors on the cells. The capsid protein substitution mutants, having capsid protein genes of MPyV, for which receptors can be found on a number of cell types, revealed no cytopathic impact, in spite of an improved viral DNA replication and assembly of virus particles. MPtV-DNA extracted from virus in lung tissue of infected mice had a heterogeneous enhancer segment. Most of the the DNA molecules had a structure varying from the standard-type. A 220 base-pair insertion at nucleotide position 142 with a concomitant deletion of nucleotides 143 to 148 was obviously a notable version. Additional genome versions demonstrated complete or partial deletions of the insertion and surrounding sequences in the viral enhancer.
The following video shows Virus Factories in Polyomavirus-Infected Cells
Contents
INTRODUCTION
VIRUS
POLYOMAVIRUSES
Introduction
Polyomaviruses as paradigms
Virus genome
Replication cycle
Early proteins
POLYOMAVIRUS REGULATORY REGIONS
Structure
Rearrangements
MOUSE PNEUMOTROPIC VIRUS
CELLULAR MOBILE DNA ELEMENTS
Classification
Functions
TEs and polyomaviruses
TEs and cancer
PRESENT INVESTIGATION
IMPETUS AND PROJECTS
CHARACTERIZATION OF MPTV LARGE T-ANTIGEN
MPTV HOST RANGE MUTANT- (KVM1) ENHANCER SUBSTITUTION
MPTV HOST RANGE MUTANT- LATE REGION SUBSTITUTION
CELLULAR TRANSPOSABLE ELEMENTS IN MPTV GENOME
FAQS………
Source: Uppsala University Library
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