= Positive-sense RNA
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\b[Positive-sense RNA] has the sequence orientation of a corresponding <messenger RNA>, rather than being its complementary template. In a positive-sense RNA virus, the entering genome can provide a coding message for <translation>, allowing production of the viral machinery that subsequently copies <RNA>. This is a sequence-and-function distinction, not a claim about the molecule's <electric charge>.
For example, a positive-sense coding segment $5'\text{-AUGGCU-}3'$ begins with the codons AUG and GCU in that reading frame. Its complementary negative-sense template is $3'\text{-UACCGA-}5'$. A polymerase copying that template produces the positive-sense sequence. Both directions and complementary bases are needed; reversing a string alone is insufficient.
Early experiments with <poliovirus> made the informational role of viral RNA concrete. Isolated RNA introduced under suitable conditions infected human cell monolayers and yielded virus of the original type. <Ribonuclease> abolished the isolated RNA's infectivity, whereas intact-virus infectivity resisted the same enzyme treatment, supporting the interpretation that exposed RNA carried the infectious genetic information.<Infectivity of ribonucleic acid from poliovirus in human cell monolayers by H. E. Alexander and others>[Abstract: HeLa and human amnion monolayers, type-specific virus production and RNAase controls.]{ref}
This does not mean naked RNA naturally enters every cell efficiently; the experiment depended on preparation and exposure conditions. It also does not eliminate the need for an <RNA-dependent RNA polymerase> during genome replication. The distinction from <Negative-sense RNA> concerns how the initial coding message is obtained, rather than whether replication ever requires a complementary strand.
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