scholarly journals Structural Analysis of Retrovirus Assembly and Maturation

Viruses ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 54
Author(s):  
Anna-Sophia Krebs ◽  
Luiza M. Mendonça ◽  
Peijun Zhang
Keyword(s):  
Life Cycle ◽  
Structural Analysis ◽  
Host Cell ◽  
Molecular Analysis ◽  
Viral Genome ◽  
Molecular Techniques ◽  
Regulatory Proteins ◽  
Virus Life Cycle ◽  
Biochemical Studies ◽  
Viral Progeny

Retroviruses have a very complex and tightly controlled life cycle which has been studied intensely for decades. After a virus enters the cell, it reverse-transcribes its genome, which is then integrated into the host genome, and subsequently all structural and regulatory proteins are transcribed and translated. The proteins, along with the viral genome, assemble into a new virion, which buds off the host cell and matures into a newly infectious virion. If any one of these steps are faulty, the virus cannot produce infectious viral progeny. Recent advances in structural and molecular techniques have made it possible to better understand this class of viruses, including details about how they regulate and coordinate the different steps of the virus life cycle. In this review we summarize the molecular analysis of the assembly and maturation steps of the life cycle by providing an overview on structural and biochemical studies to understand these processes. We also outline the differences between various retrovirus families with regards to these processes.

scholarly journals Epigenetic regulation of human papillomavirus transcription in the productive virus life cycle

2020 ◽  
Vol 42 (2) ◽  
pp. 159-171 ◽  
Author(s):  
Megan Burley ◽  
Sally Roberts ◽  
Joanna L. Parish
Keyword(s):  
Life Cycle ◽  
Host Cell ◽  
Epigenetic Regulation ◽  
Epigenetic Modification ◽  
Large Family ◽  
Human Papillomaviruses ◽  
Early Gene ◽  
Virus Transcription ◽  
Chromatin Interactions ◽  
Virus Life Cycle

AbstractHuman papillomaviruses (HPV) are a large family of viruses which contain a circular, double-stranded DNA genome of approximately 8000 base pairs. The viral DNA is chromatinized by the recruitment of cellular histones which are subject to host cell–mediated post-translational epigenetic modification recognized as an important mechanism of virus transcription regulation. The HPV life cycle is dependent on the terminal differentiation of the target cell within epithelia—the keratinocyte. The virus life cycle begins in the undifferentiated basal compartment of epithelia where the viral chromatin is maintained in an epigenetically repressed state, stabilized by distal chromatin interactions between the viral enhancer and early gene region. Migration of the infected keratinocyte towards the surface of the epithelium induces cellular differentiation which disrupts chromatin looping and stimulates epigenetic remodelling of the viral chromatin. These epigenetic changes result in enhanced virus transcription and activation of the virus late promoter facilitating transcription of the viral capsid proteins. In this review article, we discuss the complexity of virus- and host-cell-mediated epigenetic regulation of virus transcription with a specific focus on differentiation-dependent remodelling of viral chromatin during the HPV life cycle.

Host cell kinases and the hepatitis C virus life cycle

2015 ◽  
Vol 1854 (10) ◽  
pp. 1657-1662 ◽  
Author(s):  
Che C. Colpitts ◽  
Joachim Lupberger ◽  
Christian Doerig ◽  
Thomas F. Baumert
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Host Cell ◽  
Virus Life Cycle

scholarly journals Current Understanding of the Role of Cholesterol in the Life Cycle of Alphaviruses

Viruses ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 35
Author(s):  
Ivanildo P. Sousa ◽  
Carlos A. M. Carvalho ◽  
Andre M. O. Gomes
Keyword(s):  
Life Cycle ◽  
Host Cell ◽  
Cell Lines ◽  
New World ◽  
Cholesterol Metabolism ◽  
Enveloped Viruses ◽  
Important Group ◽  
Virus Life Cycle ◽  
Alphavirus Infection

Enveloped viruses rely on different lipid classes present in cell membranes to accomplish several steps of their life cycle in the host. Particularly for alphaviruses, a medically important group of arboviruses, which are part of the Togaviridae family, cholesterol seems to be a critical lipid exploited during infection, although its relevance may vary depending on which stage of the virus life cycle is under consideration and whether infection takes place in vertebrate or invertebrate hosts. In this review, the role of cholesterol in both early and late events of alphavirus infection and how viral replication may affect cholesterol metabolism are summarized, taking into account studies on Old World and New World alphaviruses in different cell lines. Moreover, the importance of cholesterol for the structural stability of alphavirus particles is also discussed, shedding light on the role played by this lipid when they leave the host cell.

scholarly journals Migration of Influenza Virus Nucleoprotein into the Nucleolus Is Essential for Ribonucleoprotein Complex Formation

mBio ◽  
2022 ◽  
Author(s):  
Sho Miyamoto ◽  
Masahiro Nakano ◽  
Takeshi Morikawa ◽  
Ai Hirabayashi ◽  
Ryoma Tamura ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Life Cycle ◽  
Viral Genome ◽  
Influenza A ◽  
Genome Replication ◽  
Ribonucleoprotein Complex ◽  
Virus Life Cycle ◽  
Viral Genome Replication ◽  
Infected Cells ◽  
Nuclear Domains

Influenza A virus ribonucleoprotein complex (RNP) is responsible for viral genome replication, thus playing essential roles in the virus life cycle. RNP formation occurs in the nuclei of infected cells; however, little is known about the nuclear domains involved in this process.

scholarly journals Role of Virally-Encoded Deubiquitinating Enzymes in Regulation of the Virus Life Cycle

2021 ◽  
Vol 22 (9) ◽  
pp. 4438
Author(s):  
Jessica Proulx ◽  
Kathleen Borgmann ◽  
In-Woo Park
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Deubiquitinating Enzyme ◽  
Deubiquitinating Enzymes ◽  
Antiviral Immune Response ◽  
Cellular Processes ◽  
Virus Life Cycle ◽  
Infected Cells ◽  
Dependent Processes

The ubiquitin (Ub) proteasome system (UPS) plays a pivotal role in regulation of numerous cellular processes, including innate and adaptive immune responses that are essential for restriction of the virus life cycle in the infected cells. Deubiquitination by the deubiquitinating enzyme, deubiquitinase (DUB), is a reversible molecular process to remove Ub or Ub chains from the target proteins. Deubiquitination is an integral strategy within the UPS in regulating survival and proliferation of the infecting virus and the virus-invaded cells. Many viruses in the infected cells are reported to encode viral DUB, and these vial DUBs actively disrupt cellular Ub-dependent processes to suppress host antiviral immune response, enhancing virus replication and thus proliferation. This review surveys the types of DUBs encoded by different viruses and their molecular processes for how the infecting viruses take advantage of the DUB system to evade the host immune response and expedite their replication.

scholarly journals Multiple effects of toxins isolated from Crotalus durissus terrificus on the hepatitis C virus life cycle

PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0187857 ◽  
Author(s):  
Jacqueline Farinha Shimizu ◽  
Carina Machado Pereira ◽  
Cintia Bittar ◽  
Mariana Nogueira Batista ◽  
Guilherme Rodrigues Fernandes Campos ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Crotalus Durissus Terrificus ◽  
Virus Life Cycle ◽  
Crotalus Durissus

Are phytoplankton population density maxima predictable through analysis of host and viral genomic DNA content?

2006 ◽  
Vol 86 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Chris M. Brown ◽  
Janice E. Lawrence ◽  
Douglas A. Campbell
Keyword(s):  
Population Density ◽  
Dna Content ◽  
Viral Genome ◽  
Particle Assembly ◽  
Phytoplankton Population ◽  
Strong Linear Correlation ◽  
Viral Progeny ◽  
A Cell ◽  
Viral Proliferation ◽  
Viral Particle Assembly

Phytoplankton:virus interactions are important factors in aquatic nutrient cycling and community succession. The number of viral progeny resulting from an infection of a cell critically influences the propagation of infection and concomitantly the dynamics of phytoplankton populations. Host nucleotide content may be the resource limiting viral particle assembly. We present evidence for a strong linear correlation between measured viral burst sizes and viral burst sizes predicted from the host DNA content divided by the viral genome size, across a diversity of phytoplankton:viral pairs. An analysis of genome sizes therefore supports predictions of taxon-specific phytoplankton population density thresholds beyond which viral proliferation can trim populations or terminate phytoplankton blooms. We present corollaries showing that host:virus interactions may place evolutionary pressure towards genome reduction of both phytoplankton hosts and their viruses.

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