Bacteriophage phi6 contains three pieces of double-stranded RNA (S, M and L) in its nucleocapsid. The pieces possess different genetic information but have similar termini. The packaging of the genomic segments is precise in that virions contain one each of the three normal segments.
The aim of this proposal is to determine how the packaging system is able to select one of each of the chromosomes and how the system acts to replicate the genome. Procapsids produced from cDNA copies of segment L in Escherichia coli are capable of packaging single stranded viral RNA, synthesizing the complementary minus strand to form double stranded RNA and then transcribing this dsRNA to form plus ssRNA. We have developed a novel and unique model for genomic packaging in phi6 that involves specific binding of genomic segments to sites on the outside of the procapsid that appear and disappear in a program that is determined by the amount of RNA within the procapsid. The model is supported by previously unexplained observations as well as findings based upon new model based predictions. We will narrow down the RNA packaging sequences to identify the nucleotides binding directly to the procapsid sites. Then we will identify the procapsid binding sites and show how their exposure changes with the packaging program. The nature of the mechanisms of selective packaging in viruses of eukaryotes having segmented genomes (reoviridae) is currently unknown. The elucidation of the mechanism for phi6 has relevance to the packaging of these viruses. Several members of the reoviridae, e.g. rotavirus and blue tongue virus, are the etiologic agents of important human and animal diseases.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Microbial Physiology and Genetics Subcommittee 2 (MBC)
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Chin, Jean
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Public Health Research Institute
United States
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Nemecek, Daniel; Qiao, Jian; Mindich, Leonard et al. (2012) Packaging accessory protein P7 and polymerase P2 have mutually occluding binding sites inside the bacteriophage 6 procapsid. J Virol 86:11616-24
Nemecek, Daniel; Cheng, Naiqian; Qiao, Jian et al. (2011) Stepwise expansion of the bacteriophage ?6 procapsid: possible packaging intermediates. J Mol Biol 414:260-71
Qiao, Xueying; Sun, Yang; Qiao, Jian et al. (2010) Interaction of a host protein with core complexes of bacteriophage phi6 to control transcription. J Virol 84:4821-5
Qiao, Xueying; Sun, Yang; Qiao, Jian et al. (2010) Characterization of Phi2954, a newly isolated bacteriophage containing three dsRNA genomic segments. BMC Microbiol 10:55
Qiao, Jian; Qiao, Xueying; Sun, Yang et al. (2010) Role of host protein glutaredoxin 3 in the control of transcription during bacteriophage Phi2954 infection. Proc Natl Acad Sci U S A 107:6000-4
Nemecek, Daniel; Heymann, J Bernard; Qiao, Jian et al. (2010) Cryo-electron tomography of bacteriophage phi6 procapsids shows random occupancy of the binding sites for RNA polymerase and packaging NTPase. J Struct Biol 171:389-96
Qiao, Xueying; Sun, Yang; Qiao, Jian et al. (2009) Temporal control of message stability in the life cycle of double-stranded RNA bacteriophage phi8. J Virol 83:633-9
Sen, Anindito; Heymann, J Bernard; Cheng, Naiqian et al. (2008) Initial location of the RNA-dependent RNA polymerase in the bacteriophage Phi6 procapsid determined by cryo-electron microscopy. J Biol Chem 283:12227-31
Qiao, Xueying; Sun, Yang; Qiao, Jian et al. (2008) The role of host protein YajQ in the temporal control of transcription in bacteriophage Phi6. Proc Natl Acad Sci U S A 105:15956-60
Farver, Ole; Chen, Ying; Fee, James A et al. (2006) Electron transfer among the CuA-, heme b- and a3-centers of Thermus thermophilus cytochrome ba3. FEBS Lett 580:3417-21

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