An Assay of RNA Synthesis in Hepatic Nuclei from Control and Streptococcus pneumoniae-Infected Rats

Hepatic nuclei were isolated, purified, and partially characterized from control and Streptococcus pneumoniae-infected rats. Biochemical and morphologic examination showed little contamination by other cell organelles. An in vitro system for the incorporation of 2-14Curidine-5-triphosphate into ribonucleic acid RNA was developed and characterized. Although the simulatory effects of cytosol on incorporation of labeled precursors into RNA have been previously reported, nuclei isolated from the livers of S. pneumoniae-infected rats were stimulated to a significantly greater extent than were nuclei isolated from the livers of control rats. In the presence of cytosol prepared from either control or infected rats, the increased incorporation of labeled precursor into RNA by nuclei isolated from infected rats was observed over broad pH and temperature ranges. The increased activity of infected nuclei was eliminated when albumin was substituted for cytosol, and could not be accounted for by differences in endogenous precursor pool size. These results are consistent with other infection-induced alterations in hepatic RNA and protein synthesis.