The mechanism of RNA virus replication and regulation课件.ppt

The mechanism of RNA virus replication and regulation ;Contents; A The Baltimore Classification of Viruses ;III dsRNA ;Rotavirus轮状病毒;一、The viruses have: 1. single-component (Totiviridae 全病毒科) 2. two-component (Birna-, Crypto- and Partitiviruses) 3. three-component (Cystoviridae囊状病毒) and multi-component (Reoviridae,呼肠孤病毒科 10-12 segments) genomes All multiple component genomes are encapsidated in a single particle. 二、Virus genome sizes: Partitiviridae分病毒: 4-9 kb ; Birnaviridae: about 6 kb Totiviridae轮状病毒: 4-7 kb ; Hypoviridae亚病毒: 10-13 kb Cystoviridae囊状病毒: 13 kb Reoviridae呼肠孤病毒: 20-27 kb All genomes apparently replicate by a conservative mechanism, wherein ds input RNA is transcribed by viral enzyme to mRNA, which both codes for protein, and acts as template for second strand synthesis;Type IV:?(+)ve-sense ssRNA ;; two components with single ORFs (Como-, Noda-, Tetri- and Potyviridae genus Bymovirus) two components with multiple ORFs (Tobra-, Furo-, Enamovirus) three components with multiple ORFs (Hordeivirus, Bromoviridae) 三、Genome sizes range from: Less than 5 kb (Levi-, Barna-, Tombusviridae), To 7-12 kb (Astro-, Como-, Picorna-, Calici-, Bromo-, Poty-, Sequi-, Toga-, Flaviviridae, Tobraviruses) To 13 kb (Arteriviruses) - 15.5 kb (Closteroviruses) To 20 - 30 kb (Coronaviridae) 四、Genome expression strategies range from : Expressing a single polyprotein from each genome component and proteolytically processing it (Picorna-, Poty-, Sequi-, Como-, Nodaviridae) Expressing proteins from 5-proximal ORFs and from subgenomic messengers (Tobamoviruses, Bromoviridae) A mixture of the two strategies (Togaviridae, Tymoviruses, Caliciviridae) ;Type V:?(-)ve-sense ssRNA ;Orthomyxoviridae 正粘病毒流感病毒;The families Paramyxo-, Rhabdo and Filoviridae are grouped together in the oder Mononegavirales, due to similarities in virion structure, gene order and rans