1. Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA.
2. Instituto de Microbiologia and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem (INCTBEB), Federal University of Rio de Janeiro, RJ – Brazil
Os resultados publicados no Journal of Virology foram produzidos pela colaboração entre a Universidade da Carolina do Norte e a Universidade Federal do Rio de Janeiro, através do Instituto de Microbiologia e o Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem.
Os vírus iniciam o processo infeccioso transferindo seu genoma através da membrana celular da célula hospedeira. Para os alphavirus o modelo popular de penetração na célula compreende a entrada o vírus através de endocitose mediada por um receptor e fusão da membrana no endossomo.
Neste estudo utilizando técnicas de microscopia eletrônica e imunocitoquímica foi demonstrado que a entrada dos alphavirus ocorre através da penetração direta na membrana plasmática através de um poro formado pelo próprio vírus e possivelmente por proteínas na célula hospedeira.
Alphavirus genome delivery occurs directly at the plasma membrane in a time and temperature dependent process.
It is widely held that Arboviruses such as the Alphavirus Sindbis gain entry to cells by a process of receptor mediated endocytosis followed by membrane fusion in the acid environment of the endosome. We have used an approach of direct observation of Sindbis virus entry into ; cells by electron microscopy and immuno-labeling of virus proteins with antibodies conjugated to gold beads. We found that upon attaching to the cell surface intact RNA containing viruses became empty shells which could only be identified by antibody labeling. We found that the rate
at which full particles were converted to empty particles increased with time and temperature. We found that this entry event takes place at temperatures which inhibit both endosome formation and membrane fusion. We conclude that entry of alphaviruses is by direct penetration of cell plasma membranes through a pore structure formed by virus and, possibly, host proteins.
J Virol (2013),
doi:10.1128/JVI.03412-12
