= Negative-sense RNA
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\b[Negative-sense RNA] is <RNA> whose sequence is complementary to the corresponding <messenger RNA> sequence. “Negative” specifies orientation relative to a coding message; it does not mean negative <electric charge>, damage, or lack of biological function. A negative-sense viral genome must first be copied into a message-compatible <Positive-sense RNA> before its encoded <proteins> can be made by <translation>.
For a short illustrative message $5'\text{-AUGGCU-}3'$, the complementary template is $3'\text{-UACCGA-}5'$, equivalently $5'\text{-AGCCAU-}3'$ when written in the conventional direction. The strands are complementary and antiparallel. Simply reversing the letters, without exchanging complementary bases, would not produce the negative-sense template. This small example shows why both sequence and direction matter.
The requirement creates a startup problem for a <virus>: if the entering genome cannot itself serve as <messenger RNA>, how can it make the enzyme needed to copy that genome? <Vesicular stomatitis virus> solves this by carrying an <RNA-dependent RNA polymerase> in its viral particle. In the 1970 experiment by <D. Baltimore>, <A. S. Huang> and <M. Stampfer>, virion preparations incorporated supplied ribonucleotide substrates into new <RNA>; the main product was complementary in sequence to the viral genome.<Ribonucleic acid synthesis of vesicular stomatitis virus, II. An RNA polymerase in the virion by D. Baltimore and others>[Abstract and virion-associated RNA-synthesis assay: complementary RNA product.]{ref}
This experiment connects a sequence classification to physical machinery packaged with the genome. <Positive-sense RNA> and <Negative-sense RNA> describe the relation of an RNA region to the coding message; identifying the sense does not by itself specify all details of genome segmentation, replication intermediates or transcription control.
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