title: Evidence for preferential copackaging of Moloney murine leukemia virus genomic RNAs transcribed in the same chromosomal site.
abstract: BACKGROUND
  Retroviruses have a diploid genome and recombine at high frequency. Recombinant proviruses can be generated when two genetically different RNA genomes are packaged into the same retroviral particle. It was shown in several studies that recombinant proviruses could be generated in each round of HIV-1 replication, whereas the recombination rates of SNV and Mo-MuLV are 5 to 10-fold lower. The reason for these differences is not clear. One possibility is that these retroviruses may differ in their ability to copackage genomic RNAs produced at different chromosomal loci.
  
  
  RESULTS
  To investigate whether there is a difference in the efficiency of heterodimer formation when two proviruses have the same or different chromosomal locations, we introduced two different Mo-MuLV-based retroviral vectors into the packaging cell line using either the cotransfection or sequential transfection procedure. The comparative study has shown that the frequency of recombination increased about four-fold when the cotransfection procedure was used. This difference was not associated with possible recombination of retroviral vectors during or after cotransfection and the ratios of retroviral virion RNAs were the same for two variants of transfection.
  
  
  CONCLUSIONS
  The results of this study indicate that a mechanism exists to enable the preferential copackaging of Mo-MuLV genomic RNA molecules that are transcribed on the same DNA template. The properties of Mo-MuLV genomic RNAs transport, processing or dimerization might be responsible for this preference. The data presented in this report can be useful when designing methods to study different aspects of replication and recombination of a diploid retroviral genome.
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Institute of Hematology and Blood Transfusion, 223059 Minsk, Republic of Belarus. oklahomych@mail.ru
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Kharytonchyk
authors.forename: Alla I
authors.initials: AI
authors.lastname: Kireyeva
authors.forename: Anna B
authors.initials: AB
authors.lastname: Osipovich
authors.forename: Igor K
authors.initials: IK
authors.lastname: Fomin
mesh_terms: D000818:Animals; D004279:DNA, Viral / Q000378:metabolism; D005822:Genetic Vectors; D016679:Genome, Viral; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics / Q000378:metabolism*; D041681:NIH 3T3 Cells; D016133:Polymerase Chain Reaction; D011533:Proviruses / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014162:Transfection; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral