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Nucleases and adenosine 3',5'-cyclic monophosphate phosphodiesterase activities in murine sarcoma virus
Abstract:
To provide information on the role of nucleases in oncogenic virus infection, the activities of 3'-nucleotide phosphodiesterase (3'-NPDase), 5'-nucleotide phosphodiesterase (5'-NPDase), acid deoxyribonuclease (DNase II), and 3',5'-cyclic AMP phosphodiesterase (cAMPDase) in spleen extracts of murine sarcoma virus-infected C57BL/6 inbred mice were studied. At the peak of tumor growth and of the cell-mediated cytotoxic response (CMC) against tumor-associated antigens, 3'-NPDase, 5'-NPDase, and DNase II all showed depressed activities in the spleen, whereas the activity of cAMPDase in the spleen increased at the peak of CMC and remained elevated thereafter. Serum enzyme activities of the infected mice were also determined, and only 3'-NPD-ase in serum correlated well with CMC. Inasmuch as the correlation of the tumor growth with CMC was established in this system, further study on tumors with variance between CMC and growth is necessary to determine if serum 3'-NPDase is a useful biochemical marker for CMC in vivo.
Insights
Nuclease activities in mice infected with murine sarcoma virus changed during tumor growth. Spleen enzymes 3'-nucleotide phosphodiesterase (3'-NPDase), 5'-nucleotide phosphodiesterase (5'-NPDase), and acid deoxyribonuclease (DNase II) decreased, while 3',5'-cyclic AMP phosphodiesterase (cAMPDase) increased.
Area of Science:
- Oncology
- Virology
- Biochemistry
Background:
- Nucleases play a role in viral infections.
- Understanding nuclease activity during oncogenic virus infection is crucial.
Purpose of the Study:
- To investigate the role of specific nucleases in murine sarcoma virus infection.
- To analyze the activities of 3'-nucleotide phosphodiesterase (3'-NPDase), 5'-nucleotide phosphodiesterase (5'-NPDase), acid deoxyribonuclease (DNase II), and 3',5'-cyclic AMP phosphodiesterase (cAMPDase) in infected mice.
Main Methods:
- Studied spleen extracts from C57BL/6 mice infected with murine sarcoma virus.
- Measured nuclease activities at the peak of tumor growth and cell-mediated cytotoxic response (CMC).
- Assessed serum enzyme activities in infected mice.
Main Results:
- 3'-NPDase, 5'-NPDase, and DNase II activities were depressed in the spleen during peak tumor growth and CMC.
- cAMPDase activity increased in the spleen at the peak of CMC and remained elevated.
- Serum 3'-NPDase activity showed a strong correlation with CMC.
Conclusions:
- Nuclease activity profiles in spleen change significantly during oncogenic viral infection.
- Serum 3'-NPDase may serve as a potential biochemical marker for in vivo cell-mediated cytotoxic response.
- Further research is needed to validate serum 3'-NPDase as a marker in tumors with varying CMC and growth rates.