Showing papers by "Arnold J. Levine published in 1970"

Deoxyribonucleic Acid Replication in Simian Virus 40-Infected Cells III. Comparison of Simian Virus 40 Lytic Infection in Three Different Monkey Kidney Cell Lines

Abstract: A comparative study of simian virus 40 (SV40) lytic infection in three different monkey cell lines is described. The results demonstrate that viral deoxyribonucleic acid (DNA) synthesis and infectious virus production begin some 10 to 20 hr earlier in CV-1 cells and primary African green monkey kidney (AGMK) cells than in BSC-1 cells. Induction of cellular DNA synthesis by SV40 was observed in CV-1 and AGMK cells but not with BSC-1 cells. Excision of large molecular weight cellular DNA to smaller fragments was easily detectable late in infection of AGMK cells. Little or no excision was observed at comparable times after infection of CV-1 and BSC-1 cells. The different kinds of responses of these three monkey cell lines during SV40 lytic infection suggest the involvement of cellular functions in the virus-directed induction of cellular DNA synthesis and the excision of this DNA from the genome.

Deoxyribonucleic acid replication in simian virus 40-infected cells. II. Detection and characterization of simian virus 40 pseudovirions.

Abstract: Purified simian virus 40 (SV40) virions, grown in primary African green monkey kidney cells labeled prior to infection with 3 H-thymidine, contain a variable quantity of 3 H-labeled deoxyribonucleic acid (DNA). This DNA is resistant to deoxyribonuclease, sediments at 250 S , and is enclosed in a particle that can be precipitated with SV40-specific antiserum. DNA-DNA hybridization experiments demonstrate that this 3 H-labeled component in purified SV40 virions is cellular DNA. When this 3 H-labeled DNA is released from purified virus with sodium dodecyl sulfate, it has an average sedimentation constant of 14 S . Sedimentation through neutral and alkaline sucrose gradients shows that this 14 S DNA is composed of a collection of different sizes of DNA molecules that sediment between 11 and 15 S . As a result of this size heterogeneity, SV40 virions containing cellular DNA (pseudovirions) have a variable DNA to capsid protein ratio and exhibit a spectrum of buoyant densities in a CsCl equilibrium gradient. Pseudovirions are enriched, relative to true virions, on the lighter density side of infectious SV40 virus banded to equilibrium in a CsCl gradient. Little or no cellular DNA was found in purified SV40 virus preparations grown in BSC-1 or CV-1 cells.