CHARACTERIZATION OF CHIMERIC FULL-LENGTH MOLECULAR CLONES OF ALEUTIANMINK DISEASE PARVOVIRUS (ADV) - IDENTIFICATION OF A DETERMINANT GOVERNING REPLICATION OF ADV IN CELL-CULTURE
Me. Bloom et al., CHARACTERIZATION OF CHIMERIC FULL-LENGTH MOLECULAR CLONES OF ALEUTIANMINK DISEASE PARVOVIRUS (ADV) - IDENTIFICATION OF A DETERMINANT GOVERNING REPLICATION OF ADV IN CELL-CULTURE, Journal of virology, 67(10), 1993, pp. 5976-5988
The ADV-G strain of Aleutian mink disease parvovirus (ADV) is nonpatho
genic for mink but replicates permissively in cell culture, whereas th
e ADV-Utah 1 strain is highly pathogenic for mink but replicates poorl
y in cell culture. In order to relate these phenotypic differences to
primary genomic features, we constructed a series of chimeric plasmids
between a full-length replication-competent molecular clone of ADV-G
and subgenomic clones of ADV-Utah 1 representing map units (MU) 15 to
88. After transfection of the plasmids into cell culture and serial pa
ssage of cell lysates, we determined that substitution of several segm
ents of the ADV-Utah 1 genome (MU 15 to 54 and 65 to 73) within an inf
ectious ADV-G plasmid did not impair the ability of these constructs t
o yield infectious virus in vitro. Like ADV-G, the viruses derived fro
m these replication-competent clones caused neither detectable viremia
10 days after inoculation nor any evidence of Aleutian disease in adu
lt mink. On the other hand, other chimeric plasmids were incapable of
yielding infectious virus and were therefore replication defective in
vitro. The MU 54 to 65 EcoRI-EcoRV fragment of ADV-Utah 1 was the mini
mal segment capable of rendering ADV-G replication defective. Substitu
tion of the ADV-G EcoRI-EcoRV fragment into a replication-defective cl
one restored replication competence, indicating that this 0.53-kb port
ion of the genome, wholly located within shared coding sequences for t
he capsid proteins VP1 and VP2, contained a determinant that governs r
eplication in cell culture. When cultures of cells were studied 5 days
after transfection with replication-defective clones, rescue of dimer
ic replicative form DNA and single-stranded progeny DNA could not be d
emonstrated. This defect could not be complemented by cotransfection w
ith a replication-competent construction.