THE PARTIAL CYTOLYSIS OF THE AMPHIBIAN ERYTHROCYTE AND LIVER PARENCYHMA CELL BY A NON-IONOGENIC SURFACE ACTIVE AGENT

In vitro transcription by isolated nuclei of Rhynchosciara americana salivary glands. Characteristics of incorporation and inhibition by alpha-amanitin

A method for the isolation of polytene nuclei from salivary glands cells of the Diptera Rhynchosciara americana is described. The stage-specific morphological pattern of the chromosome is maintained during the isolation. The isolated nuclei show two distinct RNA polymerase activities, namely I and II, characterized on the basis of ionic requirements and alpha-amanitin sensitivity. Studies of the product under the incubation conditions show that the system allows the synthesis of high-molecular weight RNA, beside a low molecular weight peak which may comprise pre-4S and 5S RNAs. Autoradiographic studies carried out in the presence or absence of the toxin alpha-amanitin showed that micronucleoli contain products of RNA polymerase type I activity (ribosomal RNA) and that the DNA puffs are engaged in alpha-amanitin sensitive RNA synthesis and thus are sites of polymerase type II activity.

Comparison of Rous sarcoma virus-specific deoxyribonucleic acid polymerases in virions of Rous sarcoma virus and in Rous sarcoma virus-infected chicken cells

Labeled virions of Rous sarcoma virus (RSV) were disrupted with detergent and analyzed on equilibrium sucrose density gradients. A core fraction at a density of approximately 1.24 g/cc contained all of the (3)H-uridine label and about 30% of the (3)H-leucine label from the virions. Endogenous viral deoxyribonucleic acid (DNA) polymerase activity was only found in the same location. Additional ribonucleic acid (RNA)- and DNA-dependent DNA polymerase activities were found at the top of the gradients. RNA-dependent and DNA-dependent DNA polymerase activities were also found in RSV-converted chicken cells. Particles containing these activities were released from cells by detergent and were shown to contain viral RNA. These particles were analyzed on equilibrium sucrose density gradients and were found to have densities different from virion cores.

Superinfection of simian virus 40-transformed permissive cells with simian virus 40

Evidence that the resistance of simian virus (SV40)-transformed permissive cells to superinfection with SV40 is due to lack of virus uptake is presented. When virus uptake is enhanced, the events of infection proceed as in normal permissive cells, resulting in production of infectious virus.

Early events in the infection of permissive cells with simian virus 40: adsorption, penetration, and uncoating

The early events in the interaction of simian virus 40 (SV40) with permissive cells were investigated. Evidence is presented that 30 min after infection intact virions penetrate the nuclei of infected cells. The uncoating of the virus is carried out in the nuclei with a complete dissociation of the viral genome from the protein coat. Opening of the circular parental deoxyribonucleic acid (DNA), i.e., conversion of component I to component II of SV40 DNA, takes place after uncoating, followed by the appearance of a new component sedimenting faster than component I at alkaline pH.