Yes

Dear Pranav, Can u please explain this..

I have taken this passage directly from Field's virology Volume 1, Chp.5 pg.132.

"Viruses with positive-sense ssRNA genomes (except the retroviruses) deliver their genomic RNAs directly to cellular ribosomes and begin the infectious cycle with translation. Accordingly, these genomic RNAs are infectious even when completely deproteinized, as was first shown for tobacco mosaic virus RNA in classic work that helped establish that genes were composed of nucleic acids rather than proteins (25). Positive-sense RNA viruses fall into two groups: those that produce subgenomic mRNAs and those that do not. For viruses in the latter group (e.g., picorna- and flaviviruses), genomic RNA directs the synthesis of a single polyprotein precursor that gives rise to both the structural and nonstructural viral proteins, which are therefore produced in equimolar amounts. After cleavage by proteases contained within the polyprotein itself, the nonstructural proteins catalyze RNA replication to produce progeny genomes that assemble with the processed structural proteins to form progeny virus particles. For positive-sense viruses in the other group, which include the astro-, calici-, toga-, corona-, and arteriviruses , genomic RNA directs the synthesis of a precursor that gives rise to only the nonstructural proteins, including the viral RdRp. This enzyme then transcribes one or more subgenomic mRNAs that encode the structural proteins. Their greater transcriptional complexity allows these viruses to produce their proteins in dissimilar amounts."

you can read about non-canonical translation of virus genomes in this review article

http://vir.sgmjournals.org/content/93/Pt_7/1385.full?sid=41fbd786-e3c7-4fd3-9718-e274a7c758ad

Try this too: http://www.mcb.uct.ac.za//tutorial/RNA%20virus%20replication.htm

Basically, any RNA that has ribosome binding sites and a recognisable ORF in the right context, with start codon, is probably translatable.

it must be + sense & with poly A tail, cap too, i think

Plus strand RNA viruses do not always use cap-dependent translation. For example the picornaviruses have an internal ribosome binding site (IRES) that allows for cap-independent translation.

Thank you all for helping me to understand some knowledge about nature of genome in virus.. In my opinion the +strand viruses that acts directly as mRNA can undergo translation with various virus or host polymerases depending on virus and they also go for genome formation for packaging. Some of the +strand also go replication to produce more copies..

Please correct if wrong..

Thankx

Dear Susan Payne

Thank you for comment.

You are right.. there are different methods on recognition by primer and translation. Some may have protein as primer, hairpin formation for primer and RNA as primer...

Hello Bivek,

You write about primers in your response to me. The word 'primer' is usually used when referring to synthesis of nucleic acids. Ribosomes assemble on mRNA, recognizing caps or IRES, but these are not usually called 'primers'. There are hairpins and RNAs used as primers for viral genome replication. Many of my students get mixed up when thinking about transcription and translation.