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Le interferon mRNA from human fibroblasts
Abstract:
Human F and Le interferon can be clearly distinguished on the basis of different antigenic properties and host range. After inoculation with Newcastle disease virus (NDV), GM-258 fibroblasts produced Le as well as F interferon; in contrast, only F interferon was detectable after stimulation with poly(I) . poly(C). Polyadenylylated mRNA isolated from fibroblasts induced with poly(I) . poly(C) or NDV was injected into Xenopus laevis oocytes and the interferon activities thus produced were analyzed. Only F interferon production was demonstrable in oocytes injected with mRNA from cells induced with poly(I) . poly(C), whereas both F and Le interferons were made in oocytes injected with mRNA from NDV-induced cultures. The time course of accumulation of F and Le interferon mRNAs in NDV-induced cells corresponded to the kinetics of F and Le interferon synthesis in intact cells. The ratio of F and Le interferons made in oocytes was similar to that observed in intact GM-258 cells. F and Le interferon mRNA activities isolated from GM-258 cells could not be separated by sucrose density gradient centrifugation. However, the profile of F mRNA activity was more heterogeneous and its peak sedimented somewhat more slowly than that of Le interferon mRNA. These results suggest that the varying ratios of F and Le interferon synthesis in different cells after different modes of stimulation are determined at the level of mRNA. The induction mechanisms of F and Le interferon mRNA synthesis appear to be closely related but not identical.
Insights
Human F and Le interferons exhibit distinct properties. Their differential production in fibroblasts, triggered by Newcastle disease virus (NDV) or poly(I)·poly(C), is regulated at the messenger RNA (mRNA) level.
Area of Science:
- Immunology
- Molecular Biology
- Virology
Background:
- Human interferons F and Le are distinct antiviral proteins with different antigenic properties and host ranges.
- Understanding the regulation of interferon production is crucial for developing effective antiviral therapies.
Purpose of the Study:
- To investigate the molecular mechanisms underlying the differential induction of human F and Le interferon synthesis.
- To determine if the regulation occurs at the level of messenger RNA (mRNA) or protein synthesis.
Main Methods:
- GM-258 fibroblasts were stimulated with Newcastle disease virus (NDV) or poly(I)·poly(C).
- Polyadenylylated mRNA was isolated from stimulated cells and injected into Xenopus laevis oocytes.
- Interferon activities produced in oocytes were analyzed and compared to those in intact cells.
- mRNA activity was further analyzed using sucrose density gradient centrifugation.
Main Results:
- NDV stimulation induced both F and Le interferon production in fibroblasts, while poly(I)·poly(C) induced only F interferon.
- mRNA from NDV-induced cells produced both F and Le interferons in oocytes, whereas mRNA from poly(I)·poly(C)-induced cells produced only F interferon.
- The ratio of F and Le interferons produced in oocytes mirrored that in intact cells, suggesting mRNA-level regulation.
- F and Le interferon mRNAs exhibited distinct sedimentation profiles, indicating differences in their molecular properties.
Conclusions:
- The differential synthesis of F and Le interferons in response to various stimuli is primarily regulated at the mRNA level.
- The induction mechanisms for F and Le interferon mRNA synthesis are closely related but not identical.
- These findings provide insights into the complex regulation of the interferon system and its implications for antiviral immunity.