Abstract
We have investigated poly(ADP-ribosyl)ation processes in human monocyte-derived macrophages and the effect of the activating cytokine, interferon γ (IFN-γ) on these processes. IFN-γ was shown to increase the activity of poly(ADP-ribose) polymerase in human macrophages. A 2–3-fold enhancement of poly(ADP-ribose) polymerase activity was observed after 3–4 h of incubation with IFN-γ, whose effects were dose-dependent and maximal at 20–50 U/ml. Staining with anti-poly(ADP-ribose) antibodies and purification of ADP-ribosylated nuclear proteins by affinity chromatography over boronate agarose showed that enhancement of poly(ADP-ribose) polymerase activity by IFN-γ was accompanied by accumulation of poly(ADP-ribose) polymers in nuclear proteins. The effects of IFN-γ on poly(ADP-ribose) polymerase activity were not due to an enhanced accumulation of the message for the enzyme, indicating that the activation of the enzyme activity was due to post-transcriptional modifications. IFN-γ was shown to induce DNA strand breaks in human macrophages. This phenomenon followed the same time-course and was evident with the same doses of IFN-γ that increased poly(ADP-ribose) polymerase activity. Since poly(ADP-ribose) polymerase is known to require DNA nicks for its activity, the capability of IFN-γ to induce DNA strand breaks can explain its effects on poly(ADP-ribosyl)ation processes.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
