RNA is a Structural Element in Retrovirus Particles

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 98; no. 9; pp. 5246 - 5251
• Main Authors: Muriaux, Delphine, Mirro, Jane, Harvin, Demetria, Rein, Alan
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.04.2001; National Acad Sciences; The National Academy of Sciences
• Subjects: Animals; Biological Sciences; Cell Line; Cricetinae; Gag protein; Gene Products, gag - genetics; Gene Products, gag - metabolism; Genetic Vectors - genetics; Genome, Viral; Genomics; Humans; Leukemia Virus, Murine - chemistry; Leukemia Virus, Murine - genetics; Leukemia Virus, Murine - metabolism; Messenger RNA; Microbiology; Molecules; Murine leukemia virus; Packaging; Particle interactions; Retroviridae; Retrovirus; Reverse Transcriptase Polymerase Chain Reaction; ribonuclease; Ribonuclease, Pancreatic - metabolism; Ribonucleic acid; RNA; RNA, Messenger - analysis; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Viral - analysis; RNA, Viral - genetics; RNA, Viral - metabolism; Semliki Forest virus; Semliki forest virus - genetics; Sequence Deletion - genetics; Viral RNA; Virion - chemistry; Virion - genetics; Virion - metabolism; Virions; Virus Assembly; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.091000398

A single retroviral protein, Gag, is sufficient for virus particle assembly. While Gag is capable of specifically packaging the genomic RNA into the particle, this RNA species is unnecessary for particle assembly in vivo. In vitro, nucleic acids profoundly enhance the efficiency of assembly by recombinant Gag proteins, apparently by acting as "scaffolding" in the particle. To address the participation of RNA in retrovirus assembly in vivo, we analyzed murine leukemia virus particles that lack genomic RNA because of a deletion in the packaging signal of the viral RNA. We found that these particles contain cellular mRNA in place of genomic RNA. This result was particularly evident when Gag was expressed by using a Semliki Forest virus-derived vector: under these conditions, the Semliki Forest virus vector-directed mRNA became very abundant in the cells and was readily identified in the retroviral virus-like particles. Furthermore, we found that the retroviral cores were disrupted by treatment with RNase. Taken together, the data strongly suggest that RNA is a structural element in retrovirus particles.