Genetic map of bacteriophage Qβ.

<p>The map shows the genes for the 4 proteins encoded by the virus [A2 (from nt 61 to nt 1320), coat (from nt 1344 to nt 1742), A1 (from nt 1344 to nt 2330, and replicase (from nt 2352 to nt 4118)], and the non-translated regions. The protein A1 synthesizes when the stop codon of the coat protein is read through by a trp-tRNA, giving rise to an elongated protein that incorporates at low amount in the capsid.