TY - JOUR
T1 - Distinct DNA exit and packaging portals in the virus Acanthamoeba polyphaga mimivirus
AU - Zauberman, Nathan
AU - Mutsafi, Yael
AU - Halevy, Daniel Ben
AU - Shimoni, Eyal
AU - Klein, Eugenia
AU - Xiao, Chuan
AU - Sun, Siyang
AU - Minsky, Abraham
PY - 2008/5
Y1 - 2008/5
N2 - Icosahedral double-stranded DNA viruses use a single portal for genome delivery and packaging. The extensive structural similarity revealed by such portals in diverse viruses, as well as their invariable positioning at a unique icosahedral vertex, led to the consensus that a particular, highly conserved vertex-portal architecture is essential for viral DNA translocations. Here we present an exception to this paradigm by demonstrating that genome delivery and packaging in the virus Acanthamoeba polyphaga mimivirus occur through two distinct portals. By using high-resolution techniques, including electron tomography and cryo-scanning electron microscopy, we show that Mimivirus genome delivery entails a large-scale conformational change of the capsid, whereby five icosahedral faces open up. This opening, which occurs at a unique vertex of the capsid that we coined the "stargate", allows for the formation of a massive membrane conduit through which the viral DNA is released. A transient aperture centered at an icosahedral face distal to the DNA delivery site acts as a non-vertex DNA packaging portal. In conjunction with comparative genomic studies, our observations imply a viral packaging pathway akin to bacterial DNA segregation, which might be shared by diverse internal membrane-containing viruses.
AB - Icosahedral double-stranded DNA viruses use a single portal for genome delivery and packaging. The extensive structural similarity revealed by such portals in diverse viruses, as well as their invariable positioning at a unique icosahedral vertex, led to the consensus that a particular, highly conserved vertex-portal architecture is essential for viral DNA translocations. Here we present an exception to this paradigm by demonstrating that genome delivery and packaging in the virus Acanthamoeba polyphaga mimivirus occur through two distinct portals. By using high-resolution techniques, including electron tomography and cryo-scanning electron microscopy, we show that Mimivirus genome delivery entails a large-scale conformational change of the capsid, whereby five icosahedral faces open up. This opening, which occurs at a unique vertex of the capsid that we coined the "stargate", allows for the formation of a massive membrane conduit through which the viral DNA is released. A transient aperture centered at an icosahedral face distal to the DNA delivery site acts as a non-vertex DNA packaging portal. In conjunction with comparative genomic studies, our observations imply a viral packaging pathway akin to bacterial DNA segregation, which might be shared by diverse internal membrane-containing viruses.
UR - http://www.scopus.com/inward/record.url?scp=45149118680&partnerID=8YFLogxK
U2 - 10.1371/journal.pbio.0060114
DO - 10.1371/journal.pbio.0060114
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C2 - 18479185
AN - SCOPUS:45149118680
SN - 1544-9173
VL - 6
SP - 1104
EP - 1114
JO - PLoS Biology
JF - PLoS Biology
IS - 5
M1 - e114
ER -