Structure and physiology of giant DNA viruses

Paving the way towards understanding the inflammatory pathways triggered by giant viruses in mammalian cells: effect of mimivirus-cell interactions on IκBα degradation

“…This region concentrates all the factors necessary for the replication and packaging of the genome during the assembly of viral particles. For APMV and TPV, the release of viral progeny invariably results in cell lysis (Colson et al, 2017a;Oliveira et al, 2019b;dos Santos Oliveira et al, 2021). Also, after ~4 hours of APMV infection, acanthamoeba cells show a round morphology with loss in adherence as a result of the cytopathic effect promoted by the viral infection.…”

“…Among its many distinguishing features, the APMV possesses a pseudo-icosahedral capsid with a size nearing 500 nm in diameter. Its particle is almost entirely covered by fibrils (125 -140 nm), save for the stargate, feature that plays a role in the liberation of the virion internal contents, characterized by the presence of a star-shaped seal-like structure (La Scola et al, 2003;Schard et al, 2020;dos Santos Oliveira et al, 2021). Besides the gigantic particle size, its genome is also unique, being formed by a double-stranded DNA nearing 1.2 Mpb in size and encoding genes related to the expression of over 1000 proteins, transporter RNA (tRNA), tRNA aminoacylation, and non-coding RNA, all never seen before in sequenced viral genomes (La Scola et al, 2003;Raoult et al, 2004, Legendre et al, 2011.…”

“…Although their function is still unknown, it is widely believed that fibrils play an important role in GVs infection cycles. They are found in almost all the different (known) GV families (with exception of Pacmanviruses, Cedratviruses, and Pithoviruses), although they are located at distinct sites in the particle (dos Santos Oliveira et al, 2021). Data published by Kuznetsov and collaborators have shown through atomic force microscopy that the APMV capsid surface is coated by a protein matrix with high levels of sugar.…”

Editorial overview: Special issue on virus structure and expression in current opinion in virology

“…The most advanced experimental techniques used to characterize virus particles and virus proteins, including cryogenic electronic microscopy and nuclear magnetic resonance, were thoroughly reviewed [ 1 , 2 ]; new developments in molecular dynamics simulation and other computational strategies to study virus structure and proteins were also described [ 3 ]; an elegant integrative approach combining experimental and computational methods to characterize at atomic-level the structures and dynamics of HIV-1 capsids were carefully shown [ 4 ]; pivotal examples of the structure and functional characterization of important targets for antiviral development against SARS-CoV 2 and flaviviruses were described [ 5 , 6 , 7 ]. Also, discoveries on giant viruses, which have recently shaken the virology community, were aborded, and revisions on important viral protein drug targets were made [ 8 , 9 ].…”

“…Recent findings over giant viruses with larger sizes, huge DNA coding capacity, complex structures, and diverse morphologies have recently surprised the virology scientific community. Cortines et al [ 8 ] reviewed the structure and physiology of giant DNA viruses. Indeed, many different giant viruses have been discovered since the first identification of the Acanthamoeba polyphaga mimivirus in 2003.…”