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Radiation leukemia virus and its effect on H-2 gene expression
Abstract:
In this report we demonstrate that lowered expression of the H-2 antigens on RadLV-induced tumour cells is a result of depressed levels of stable mRNA in these cells. Whether this observation is a result of lowered transcription or of mRNA instability is under investigation. In an effort to determine which viral sequences are essential for mediating both the H-2 regulatory function and the transforming function of RadLV, we have begun to assemble newly integrated proviral genomes from tumours. The restriction enzyme cleavage sites of four isolates are presented; these isolates differ substantially from RadLV genomes previously presented. One of these molecular clones is shown to encode a non-defective B-tropic, ecotropic virus which when reinjected into resistant mouse strains can mediate the up-regulation of H-2Dd antigen expression. Finally, possible mechanisms of H-2 regulation are discussed.
Insights
Lowered H-2 antigen expression in RadLV-induced tumors stems from reduced mRNA levels. Researchers are investigating viral sequences for H-2 regulation and transforming functions, identifying new viral genomes.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- Reduced expression of H-2 antigens on tumor cells can impact immune surveillance.
- Retroviral infections, such as with RadLV, can alter host cell gene expression.
- Understanding viral gene functions is crucial for cancer research.
Purpose of the Study:
- To investigate the molecular basis for lowered H-2 antigen expression in RadLV-induced tumors.
- To identify viral sequences responsible for H-2 regulation and tumor transformation.
- To characterize novel RadLV proviral genomes.
Main Methods:
- Analysis of mRNA levels in tumor cells.
- Assembly and characterization of integrated proviral genomes from tumors.
- Restriction enzyme digestion to analyze viral genome structure.
- Re-injection of viral clones into mouse models.
Main Results:
- Lowered H-2 antigen expression is linked to depressed stable mRNA levels.
- Novel RadLV proviral genome isolates with distinct restriction enzyme cleavage sites were identified.
- One molecular clone encoded a virus capable of up-regulating H-2Dd antigen expression in mice.
Conclusions:
- The study elucidates a mechanism for altered H-2 antigen expression in viral-induced tumors.
- Novel viral genomes offer insights into RadLV's oncogenic and immunomodulatory functions.
- Further research is needed to fully understand the mechanisms of H-2 regulation by viral sequences.