Proč viry způsobují onemocnění?

Prezentace na téma: "Proč viry způsobují onemocnění?"— Transkript prezentace:

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2 Proč viry způsobují onemocnění?
Co jsou viry - jsou živé? Metody studia struktury virů: rentgenová krystalografie kryo-elektronová mikroskopie Viry studované v Laboratoři strukturní virologie: pikornaviry včelí viry Leishmania RNA virus bakteriofág 812K1 Albert Bosch highlights that “according to data provided by the World Health Organization, viral diseases represent two thirds of the total number of medical appointments due to infections.

3 Infekce chřipkou

4 “Virion” – infekční virová partikule
Dvě formy existence viru: “Virion” – infekční virová partikule Infekce buňky Carrier of genetic information from cell to cell: - "extracellular organelle” - packages viral genome - escapes from infected cell - survives transfer from one cell to another - attaches, penetrates, initiates replication in new host cell

5 Viruses as pathogens - viruses bear the genetic information needed to harness cellular biosynthetic machinery and replicate itself - hence, selective advantage for virus may be selective disadvantage for host - some of the most deadly pathogens: polio, HIV, Ebola, SARS, influenza, smallpox - evolution of host defense (immunity)

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7 Jsou viry živé? Znaky shodné s obvyklou definicí života
Znaky odlišné od obvyklé definice života Mají geny Nemají buněčnou strukturu Vyvíjejí se (evoluce) Nemají metabolismus Podléhají přirozené selekci Pro rozmnožení potřebují hostitelskou buňku Rozmnožují se Nové viry vznikají složením z částí These features show that viruses are simple macromolecular machines and thus we can aspire to understand them at the atomistic level.

8 Cyklus buněčného dělení

9 dsDNA dsDNA ssRNA Proteiny

10 dsDNA DNA ssRNA RNA Proteiny Proteiny
Viry Buněčné organismy Replikace dsDNA DNA Transkripce ssRNA RNA Proteiny Translace Proteiny

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12 Struktury virionů Ikosahedrální Helikální Komplexní Nepravidelné

13 WILHELM CONRAD RÖNTGEN (1845-1923)
1901 Nobel Laureate in Physics discovery of the remarkable rays subsequently named after him

14 MAX VON LAUE (1879-1960) 1914 Nobel Laureate in Physics
for his discovery of the diffraction of X-rays by crystals

15 Wavelength and diffraction

16 Wavelength comparison of X-rays and visible light

17 70μm

18 James Batcheller Sumner (1879-1960)
1946 Nobel Laureate in Chemistry for his discovery that enzymes can be crystallized

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20 1962 Nobel Laureates in Physiology and Medicine
FRANCIS HARRY COMPTON CRICK (1916~2004) JAMES DEWEY WATSON (1928~) MAURICE HUGH FREDERICK WILKINS (1916~2004) 1962 Nobel Laureates in Physiology and Medicine for their discoveries concerning the molecular structure of nuclear acids and its significance for information transfer in living material. James Watson and Francis Crick Maurice Wilkins Rosalind Franklin

21 Max Ferdinand Perutz (1914 – 2002) John Cowdery Kendrew (1917 – 1997)
1962 Nobel Laureate in Physics for their studies of the structures of globular proteins

22 Information from X-ray diffraction experiment
z x [0;0;0]

23 1. Virus purification 2. Crystallization 3. Diffraction data 4. Solve structure

24 1. Virus purification 2. Grid preparation 3. cryo-EM 4. Reconstruction

25 McMinn et al. Clin Infect Dis 2001. Image by Heng Soy, KI Media 2012.
Picornaviry Rhinoviry – 40% “nachlazení” – finanční náklady $16bn/rok v USA Enteroviry (EV71) – nemoc rukou, nohou a úst – encefalitida I would like to start my presentation by defining biological significance of my project. My research is focused on structural studies of picornaviruses that include some of the most common human pathogens. For example, rhinoviruses are responsible for about 40$ of common cold cases. The economic damage caused by rhinoviruses was estimated to be 16bn dollars per year in the united states alone. Similar expenses are expected for European union. Enterovirus 71 induces yearly outbreaks of hand-foot-and-mouth disease mostly in south-east Asia. About 5% of the infected children develop encephalitis that can be fatal or result in permanent brain damage. This magnetic resonance image shows inflammation in left section of cerebellum caused by EV71 infection. The three years old patient lost ability to speak. Currently no antiviral drugs are available against rhinoviruses or enteroviruses. More basic research is needed to improve our understanding of picornavirus biology to allow identification of new targets for antiviral drugs. My research will address these requirements by -> next slide McMinn et al. Clin Infect Dis Image by Heng Soy, KI Media 2012.

26 Životní cyklus pikornavirů
Virus replication factory … aspiring to answer basic biological questions about picornavirus life cycle. It is well established that picornaviruses enter cells by receptor mediated endocytosis. However, it is not known how is the picornavirus ssRNA genome delivered from virions across the membrane of the endosome into cell cytoplasm. That is our first research question. When in the cytoplasm the genome is translated into a polyprotein that is then cleaved into functional subunits. The viral proteins induce formation of so called virus-replication factories that contain lipid vesicles derived from intra-cellular membranes, viral and cellular proteins, ribosomes and viral RNAs. We will use modern cryo-electron tomography approaches to characterize the factories on molecular level. In addition we will structurally characterize picornavirus genome replication and recombination – processes that happen in the vicinity of the replication factories. Finally, we will determine picornavirus virion assembly mechanism.

27 Včelí viry … aspiring to answer basic biological questions about picornavirus life cycle. It is well established that picornaviruses enter cells by receptor mediated endocytosis. However, it is not known how is the picornavirus ssRNA genome delivered from virions across the membrane of the endosome into cell cytoplasm. That is our first research question. When in the cytoplasm the genome is translated into a polyprotein that is then cleaved into functional subunits. The viral proteins induce formation of so called virus-replication factories that contain lipid vesicles derived from intra-cellular membranes, viral and cellular proteins, ribosomes and viral RNAs. We will use modern cryo-electron tomography approaches to characterize the factories on molecular level. In addition we will structurally characterize picornavirus genome replication and recombination – processes that happen in the vicinity of the replication factories. Finally, we will determine picornavirus virion assembly mechanism.

28 Leishmania RNA virus 1 metastasis to nasopharyngeal tissues
Free Dictionary Ives et al. Science, 2011 Olivier. Nature, 2011 cutaneous leishmaniasis

29 Totiviry - Leishmania RNA virus 1 (LRV1)
Totivirus RNA lack M7G Cap, its translation is possible because capsid proteins have de-capping activity and thus generate decoy for cellular RNA-degradation machinery. Mutations in the de-capping active site greatly reduce virus protein production – no dsRNA is generated (this happens only in particles). Furthermore de-capping activity of LA virus can be inhibited with 7-methyl-GDP. cryo-EM tomography of Leishmania promastigotes in lysosome conditions to study release of the LA-virus from cells (Leishmania cells are 500nm tick, LA is 40nm in diameter) cryo-EM tomography of Leishmania promastigotes in lysosome Fujimura et al. PNAS, 2011 Naitow et al. NSMB 2002

30 Kryo-EM fága 812 infikujícího S. aureus
Daniel Němeček, Jiří Nováček, Lubomír Kováčik

31 Infekce fágem T4

32 Proč viry způsobují onemocnění?
Co jsou viry - jsou živé? Metody studia struktury virů: rentgenová krystalografie kryo-elektronová mikroskopie Albert Bosch highlights that “according to data provided by the World Health Organization, viral diseases represent two thirds of the total number of medical appointments due to infections.

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37 Picornavirus virion