Adenovirus type 5 fiber knob domain has a critical role in fiber protein synthesis and encapsidation.
Adenovirus serotype 5 (Ad5) vectors carrying knobless fibers designed to remove their natural tropism were found to have a lower fiber content than recombinant Ad5 with wild-type (WT) capsid, implying a role for the knob-coding sequence or/and the knob domain in fiber encapsidation. Experimental data using a variety of fiber gene constructs showed that the defect did not occur at the fiber mRNA level, but at the protein level. Knobless fiber proteins were found to be synthesized at a significant slower rate compared with knob-carrying fibers, and the trimerization process of knobless fibers paralleled their slow rate of synthesis. A recombinant Ad5 diploid for the fiber gene (referred to as Ad5/R7-ZZ(wt)/E1 : WT-fiber) was constructed to analyse the possible rescue of the knobless low-fiber-content phenotype by co-expression of WT fiber. Ad5/R7-ZZ(wt)/E1 : WT-fiber contained a knobless fiber gene in its natural location (L5) in the viral genome and an additional WT fiber gene in an ectopic position in E1. Knobless fiber was still synthesized at low levels compared with the co-expressed E1 : WT fiber and the recovery of the two fiber species in virus progeny reflected their respective amounts in the infected cells. Our results suggested that deletion of the fiber knob domain had a negative effect on the translation of the fiber mRNA and on the intracellular concentration of fiber protein. They also suggested that the knob control of fiber protein synthesis and encapsidation occurred as a cis effect, which was not modified by WT fiber protein provided in trans by the same Ad5 genome.
Henning
Petra
P
Institute for Biomedicine, Department of Microbiology and Immunology, University of Göteborg, PO Box 435, SE 40530 Göteborg, Sweden.|Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Lundgren
Emma
E
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Carlsson
Mattias
M
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Frykholm
Karolin
K
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Johannisson
Jenny
J
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Magnusson
Maria K
MK
Institute for Biomedicine, Department of Microbiology and Immunology, University of Göteborg, PO Box 435, SE 40530 Göteborg, Sweden.|Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Tång
Erika
E
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Franqueville
Laure
L
Laboratoire de Virologie et Pathogénèse Virale, Université Claude Bernard de Lyon and CNRS UMR-5537, Faculté de Médecine RTH Laennec, 7 Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
Hong
Saw See
SS
Laboratoire de Virologie et Pathogénèse Virale, Université Claude Bernard de Lyon and CNRS UMR-5537, Faculté de Médecine RTH Laennec, 7 Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
Lindholm
Leif
L
Got-A-Gene AB, Östra Kyviksvägen 18, SE 42930 Kullavik, Sweden.
Boulanger
Pierre
P
Laboratoire de Virologie Médicale, Domaine Rockefeller, Hospices Civils de Lyon, 8 Avenue Rockefeller, 69373 Lyon Cedex 08, France.|Laboratoire de Virologie et Pathogénèse Virale, Université Claude Bernard de Lyon and CNRS UMR-5537, Faculté de Médecine RTH Laennec, 7 Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism*; D000956:Antigens, Viral / Q000096:biosynthesis* / Q000737:chemistry; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins / Q000096:biosynthesis* / Q000737:chemistry; D002460:Cell Line; D017353:Gene Deletion; D005822:Genetic Vectors / Q000378:metabolism; D006801:Humans; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology
D000956:Antigens, Viral; D036022:Capsid Proteins; C018315:hexon capsid protein, Adenovirus