Leaky scanning is a technique commonly employed by viruses to express multiple proteins from a single sequence of RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

. The nucleotides surrounding the stop codon can disturb the ribosome

Ribosome

A ribosome is a component of cells that assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule....

causing it to shift reading frames and continue to translate past the stop codon. This technique can also be used to control the level of gene expression as the genes on the alternate open reading frame are translated less frequently.