Nguyen Le Tam Nhan
10672137
Midterm Assignment
The role of nuclear import for influenza A virus infection
The flu, is characterized as an infection of the respiratory tract caused by influenza viruses. Influenza infection is commonly ranked as one of the most dangerous diseases on Earth because it affects all age groups and can re-occur in any individual. Influenza A, B and C viruses belong to the orthomyxovirus, which is the family of enveloped viruses with segmented, single-stranded, negative-sense RNA genome (Calder et al., 2010; Cox & Subbarao, 1999). Type C cause sporadic mild influenza-like illness in children. Type B are known to cause recurring regional and local epidemic disease, but it is only found in human. Type A virus is the most
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Each segment is coated with multiple copies of nucleoprotein (NP) to form a nucleocapsid with helical symmetry and the length varies from approximately 30 to 110nm (Ruigrok & Baudin, 1995). Beside RNAs and NPs, the vRNP core is also packed with the RNA polymerase proteins, polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2) and polymerase acidic protein (PA). Interestingly, some other proteins that are expressed at high level during viral replication but are not structural components of the mature virion, the non-structural protein 1 (NS 1) and nuclear export protein (NEP)/NS2. NS1 is a multi-functional protein with a major role in evasion of the host immune system because it is the interferon α/β antagonist (Hale et al., 2008). NS2 (NEP), plays a crucial role in mediating the export of viral RNPs from the cell nucleus during replication (O'Neill et al., …show more content…
Some viral transcripts require splicing and since influenza virus does not encode splicing machinery, it is dependent on host splicing, an activity related to the cellular DNA-dependent RNA polymerase transcription. Indeed, influenza A virus possesses eight vRNA segments, which have been shown to encode up to 17 proteins. Segment 2 encodes the PB1, PB1-F2, and PB1-N40 by using alternative translation initiation sites (Gibbs et al., 2001; Wise et al., 2009). PB1-F2 can be expressed in many strains of influenza virus, but not all. This protein is found to be involved in the enhancement of apoptosis in host cell (Honda & Ishihama, 1997). Segment 3 encodes the polymerase acidic (PA) proteins PA and PA-X by a ribosomal frameshift, as well as two additional N-terminally truncated forms (PA-N155 and PA-N182) by using alternative translation initiation sites (Jagger et al., 2012; Muramoto et al., 2013). By using alternative mRNA splicing, three proteins, the matrix (M) protein M1 and ion channel proteins M2 and M42, and three other proteins, the NS1 and NS2/NEP are produced from segment 7 and segment 8 respectively. Additionally, previous studies
Like other negative-stranded RNA viruses, the G protein of rabies virus binds to the host cell membranes and penetrates into the host cytoplasm by pinocytosis. The virions are composed of cytoplasmic vesicles, fuse to cytoplasmic membrane and release RNP into the cytoplasm. The core starts primary transcription of the five complementary monocistronic messenger RNAs by using the virion-associated RNA-dependent RNA polymerase. Each mRNA is translated to an individual viral protein. After synthesis and replication of the genomic RNA, the full length, positive-stranded RNA is completed and becomes the template for the next negative-stranded RNA. In the assembly process, the N-P-L complex encapsulates negative-stranded genomic RNA to be made up of RNP core and the M protein consists of a capsule or matrix that su...
RSV is an enveloped, cytoplasmic, pleomorphic virus with negative single stranded RNA (3). This virus belongs in the paramuxoviridae family and in the subfamily Penumovirinae. It has a single serotype and two antigenic subtypes, A or B. In total, 8 out of the total ten RSV proteins are seen in infected cells and virions, eight being structural and two being non-structural (3). The viral envelope has three glycoproteins: G, F, and SH protein (4). In addition, RSV has 5 other structure proteins which include L, N, P, M and M2-1 (4). Two non-structural proteins: NS1 and NS2 are identified with RSV, but it is still unknown whether these two proteins are a part of the assem...
The Influenza virus is a unique respiratory viral disease that can have serious economic and social disruption to society. The virus is airborne transmitted through droplets release by coughing or sneezing from an infected person or by touching infected surfaces. Symptoms range from mild to severe and may even result in death. People with the virus usually experience fever, headache, shivering, muscle pain and cough, which can lead to more severe respiratory illness such as pneumonia. People most susceptible to the flu virus are elderly individuals and young children as well as anyone whose health or immune system has been compromise. The most effective way to counteract the influenza virus is to get the flu vaccine which is available by shots or nasal spray before the flu season as well as practicing safe hygiene. (CDC, 2013)
We have aimed to generate escape mutants under the selection of our highly potent neutralizing antibody F10 which has been extensively characterized for structural insights into the mechanisms of epitope-specific neutralization. This F10 antibody is particularly valuable for the immune-driven viral evolution studies as this antibody targets highly conserved pocket in the stem region shared with the diverse influenza subtyupes and function critical for viral fusion. Therefore, characterizing permitted evolutionary routes of the virus over the course of F10-type immune selection may serve as templates for the design of universal influenza vaccine and treatment strategies against all types of influenza viruses including those emergent pandemic strains. Selection of VN/04 (H5N1) or A/PR/8 virus escape mutants with F10 antibody was performed in MDCK cells under conditio...
Loo, Yueh-Ming and Michael Gale, Jr. “Influenza: Fatal Immunity and the 1918 Virus.” Nature 445 (2007): 267-268. 23 July. 2008 .
Influenza is a major public health problem which has outbreaks all over the world. Resulting in considerable sickness and death rates. Furthermore, it is a highly infectious airborne disease and is caused by the influenza virus. Influenza is transmitted easily from one person to another person, which has a great impact on society. When a member of society becomes sick, it is more prone to spread to other people.
The influenza pandemic of 1918-1919 killed more people than the Great War, known today as World War I (WWI), at somewhere between twenty and forty million people. (1) Influenza is a virus that appeared in 1918 and caused a pandemic. It made an enormous impact that is still significant to the world today. It has pushed scientists to make advancements in the medicine and vaccination industry that continue to grow each and every day. Influenza may be a horrible thing, but without it we wouldn’t be where we are today.
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“Selecting the Viruses in the Seasonal Influenza (Flu) Vaccine.” Centers for Disease Control and Prevention. USA.gov, 9 March 2011. Web. 19 Jan. 2010
"Virus-Host Cell Interactions during Hepatitis C Virus RNA Replication: Impact of Polyprotein Expression on the Cellular Transcriptome and Cell Cycle Association with Viral RNA Synthesis -- Scholle Et Al. 78 (3): 1513 --." The Journal of Virology. Web. 24 Mar. 2010. .
Influenza or flu is caused by RNA viruses of the family orthomyxoviridae, that affects the nose, throat, and lungs- the respiratory system. The common symptoms are: fever and respiratory problems, such as cough, sore throat,stuffy nose, as well as headaches and muscle aches. Influenza viruses are spread mainly by droplets made from people coughing, sneezing or talking while having the flu. These droplets can land in the mouths or noses of people or can inhaled into the lungs. It is least common for the virus to spread by touching an infected surface then their mouth or nose. Flu viruses are divided into 3 categories, A, B, C. A and B are responsible for problems in the respiratory system that typically occurs during the winter. Influenza types C is quite different from A and B. Type C only cause mild respiratory symptom or none at all.
So now we have an RNA strand. From this strand the protein will be synthesized, this is called translation (RNA is translated into protein). A protein is made from amino acids; these form a strand. I show the protein strand as a linear line, but in reality complex interactions between amino acids lead to 3 dimensional forms that are essential for the functioning of the protein. The translation of RNA to protein is different than the synthesis of RNA from DNA (transcription). When the DNA was transcribed into RNA, one base of DNA corresponded to one base of RNA, this 1 to 1 relation is not used in the translation to protein. During this translation, 1 amino acid is added to the protein strand for every 3 bases in the RNA. So a RNA sequence of 48 bases codes for a protein strand
The swine influenza or swine flu is a respiratory disease in pigs that is caused by the type A influenza viruses. These viruses are referred to as swine flu viruses but scientifically the main virus is called the swine triple reassortant (tr) H1N1 influenza virus. When the viruses infect humans they are called variant viruses. This infection has been caused in humans mainly by the H1N1v virus in the United States. The H1N1 virus originates in animals due to improper conditions and the food they ingest. The virus stays in latency form, thus harmless to the respective animal. The longer the animals survive the more likely the virus is to develop and strengthen making it immune to vaccines. The virus reproduced through the lytic cycle. The virus injects its own nucleic acids into a host cell and then they form a circle in the center of the cell. Rather than copying its own nucleic acids, the cell will copy the viral acids. The copies of viral acids then organize themselves as viruses inside of the cell. The membrane will eventually split leaving the viruses free to infect other cells.
The Flu was first founded in Seattle September, 1918. The avian flu can also be known as the “Bird Flu”. The bird flu is being passed around by migratory birds. It can be transmitted from birds to mammals and in some limited circumstances to humans. The flu will also be known as the H5N1 virus. The H5N1 virus has raised concerns about a potential human pandemic because its virulent (deadly; extremely dangerous) and it can evolve like other influenza viruses. As many other viruses and illnesses the flu can be a lot more deadlier. When you get the flu the lungs are severely harmed from infected cells called macrophages and T-cells. The virus can spread way beyond the lungs but generally do not. Many people catch the flu and think they have the common cold because of some of the same symptoms. But actually the flu can be more dangerous if you don’t treat it immediately.
In 1918-19 approximately 50 million deaths were a detriment of the Spanish H1N1 virus pandemic; a respiratory virus. According to the World Health Organization, the second Influenza A H1N1 pandemic in 2009 spread to more than 200 countries causing more than 18 000 deaths. Before the World Health Organization had announced the official end of the pandemic in August 2010, in July 2009 the World Health Organization sent out a phase 6 warning that H1N1 could soon be a global pandemic. It is important to recognize that the 2 different outbreaks had different A/H1N1strains effecting the world population; this suggests A/H1N1has a high ability for mutation, severely complicating the human body’s natural immune mechanism of antigenic drift. (Qi-Shi Du et al., 2010)