Replication Rhabdoviridae

1 replication

1.1 clades
1.2 proposed classifications
1.3 prototypical rhabdoviruses

replication

electron micrograph of 2 plant rhabdovirus particles

viral replication cytoplasmic. entry host cell achieved attachment of viral g glycoproteins host receptors, mediates clathrin-mediated endocytosis. replication follows negative stranded rna virus replication model. negative stranded rna virus transcription, using polymerase stuttering method of transcription. virus exits host cell budding, , tubule-guided viral movement. transmission routes zoonosis , bite.

replication of many rhabdoviruses occurs in cytoplasm, although several of plant infecting viruses replicate in nucleus.. in order replication, both l , p protein must expressed regulate transcription. l protein have lot of enzymatic actiivites such rna replication, capping mrnas phospholorylation of p. l protein gives feature in replication in cytopolasm. transcription results in 5 monocistronic mrnas being produced because intergenic sequences act both termination , promoter sequences adjacent genes. type of transcription mechanism explained stop-start model( stuttering transcription). owing stop-start model, large amounts of structural proteins produced. according model, virus-associated rna polymerase starts firstly synthesis of leader rna , 5 mrna produce n,p,m,g,l proteins, respectively. after leader rna produced, polymerase enzyme reinitiates virion transcription on n gene , proceeds synthesis until ends 3′ end of chain.then, synthesis of p mrnas made same enzyme new starter sinyal. these steps continue until enzyme arrives end of l gene. during transcription process, polymerase enzyme may leave template @ point , bound @ 3′ end of genome rna start mrna synthesis again. process results concentration gradient of amount of mrna based on place , range 3′ end. in circumstances, amounts of mrna species change , produced n>p>m>g>l proteins. during synthesis mrnas processed introduce 5 cap , 3’ polyadenylated tail each of molecules .this structure homologous cellular mrnas , can translated cellular ribosomes produce both structural , non-structural proteins.

genomic replication requires source of newly synthesized n protein encapsidate rna. occurs during synthesis , results in production of full length anti-genomic copy. in turn used produce more negative-sense genomic rna. viral polymerase required process, how polymerase engages in both mrna synthesis , genomic replication not understood.

replication characteristically occurs in inclusion body within cytoplasm, bud through various cytoplasmic membranes , outer membrane of cell. process results in acquisition of m + g proteins, responsible characteristic bullet- shaped morphology of virus.

clades

these viruses fall 4 groups based on rna polymerase gene. basal clade appears novirhabdoviruses, infect fish. cytorhabdoviruses , nucleorhabdoviruses, infect plants, sister clades. lyssaviruses form clade of own more closely related land vertebrate , insect clades plant viruses. remaining viruses form number of highly branched clades , infect arthropods , land vertebrates.

a 2015 analysis of 99 species of animal rhabdoviruses found fell 17 taxonomic groupings, 8 – lyssavirus, vesiculovirus, perhabdovirus, sigmavirus, ephemerovirus, tibrovirus, tupavirus , sprivivirus - recognized. authors proposed 7 new taxa on basis of findings: almendravirus , bahiavirus , curiovirus , hapavirus , ledantevirus , sawgravirus , sripuvirus . 7 species did not group others suggesting need additional taxa.

proposed classifications

curioviruses group of 4 viruses isolated biting midges (culicoides), sandflies (lutzomyia ) , mosquitoes (coqillettidia , trichoprosopon) captured in forests of south america , caribbean.

bracorhabdoviruses derived acronym brazilian amazonian culicoides rhabdoviruses.

an unofficial supergroup – dimarhabdovirus – refers genera ephemerovirus , vesiculovirus. number of other viruses have not been classified genera belong taxon. supergroup contains genera species replicate in both vertebrate , invertebrate hosts , have biological cycles involve transmission haematophagous dipterans.

prototypical rhabdoviruses

the prototypical , best studied rhabdovirus vesicular stomatitis indiana virus. preferred model system study biology of rhabdoviruses, , mononegaviruses in general.

the mammalian disease rabies caused lyssaviruses, of several have been identified.

rhabdoviruses important pathogens of animals , plants. rhabdoviruses transmitted hosts arthropods, such aphids, planthoppers, leafhoppers, black flies, sandflies, , mosquitoes.

in september 2012, researchers writing in journal plos pathogens described species of rhabdovirus, called bas-congo virus or basv, responsible 4 cases of viral hemorrhagic fever in bas-congo district in 2009. 2 non-fatal cases occurred in healthcare workers treating other 2, suggesting possibility of person-to-person transmission.