Virion structure and in vitro genome release mechanism of dicistrovirus Kashmir bee virus

MUKHAMEDOVA, LIYA; FÜZIK, TIBOR; NOVÁCEK, JIRÍ; HREBÍK, DOMINIK; PRIDAL, ANTONÍN; MARTI, GERARDO A.; GUÉRIN, DIEGO M.A.; PLEVKA, PAVEL

JOURNAL OF VIROLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington; Año: 2021

0022-538X

Infections of Kashmir bee virus (KBV) are lethal for honeybees and have been associated with colony collapse disorder. KBV and closely related viruses contribute to the ongoing decline in the number of honeybee colonies in North America, Europe, Australia, and other parts of the world. Despite the economic and ecological impact of KBV, its structure and infection process remain unknown. Here we present the structure of the virion of KBV determined to a resolution of 2.8 Å. We show that the exposure of KBV to acidic pH induces a reduction in inter-pentamer contacts within capsids and the reorganization of its RNA genome from a uniform distribution to regions of high and low density. Capsids of KBV crack into pieces at acidic pH, resulting in the formation of open particles lacking pentamers of capsid proteins. The large openings of capsids enable the rapid release of genomes and thus limit the probability of their degradation by RNases. The opening of capsids may be a shared mechanism for the genome release of viruses from the family Dicistroviridae.