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An association between globin messenger RNA and 60S RNA derived from Friend leukemia virus
Abstract:
The association between certain cellular RNAs and purified RNA tumor viruses prompted us to examine the possibility that specific host messenger RNAs might also be incorporated into RNA tumor viruses. Using a mouse cell line infected with Friend leukemia virus, T-3-Cl-2, which can be induced to accumulate mouse-globin messenger RNA, we show that mouse-globin messenger RNA sequences are present in viral particles purified from the culture medium of globin-producing cells. These globin messenger RNA sequences are absent from viral particles derived from T-3-Cl-2 cells that are not producing globin messenger RNA. Virus-associated globin messenger RNA sequences sediment in association with the 60S viral RNA complex as well as in free, 9S form. However, under mild denaturing conditions which result in the conversion of viral 60S RNA to 30S and smaller forms, all the globin sequences sediment as 9S RNA. Appropriate control experiments indicate that the virus-associated globin messenger RNA is resistant to degradation by exogenous ribonuclease; that exogenously added globin messenger RNA does not become associated with the 60S viral RNA complex; and that globin messenger RNA can be detected in virions derived from cells both induced for and constitutively synthesizing globin messenger RNA.
Insights
Specific host messenger RNAs, like mouse-globin messenger RNA, are incorporated into RNA tumor viruses. This occurs when infected cells produce the messenger RNA, indicating a direct link between cellular RNA and viral particles.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Cellular RNA association with RNA tumor viruses was previously observed.
- The potential incorporation of host messenger RNA into these viruses remained unexplored.
Purpose of the Study:
- To investigate if specific host messenger RNAs are incorporated into RNA tumor viruses.
- To determine the presence of mouse-globin messenger RNA in viral particles.
Main Methods:
- Utilized a mouse cell line (T-3-Cl-2) infected with Friend leukemia virus.
- Induced globin messenger RNA production in cells.
- Purified viral particles from cell culture medium.
- Analyzed viral RNA content using sedimentation assays and ribonuclease resistance tests.
Main Results:
- Mouse-globin messenger RNA sequences were detected in purified viral particles from globin-producing cells.
- These globin sequences were absent in viral particles from non-producing cells.
- Virus-associated globin messenger RNA was found in both 60S viral RNA complexes and free 9S forms, converting to 9S under denaturing conditions.
- Globin messenger RNA within virions showed resistance to exogenous ribonuclease.
Conclusions:
- Specific host messenger RNAs, exemplified by mouse-globin messenger RNA, can be incorporated into RNA tumor viruses.
- The presence of host messenger RNA in virions is dependent on cellular production of that specific RNA.
- This finding has implications for understanding viral assembly and potential roles of host RNA in viral biology.