Recoding in Bacteriophages
There are two classes of translational recoding, both frameshifts, known in the dsDNA tailed phages. The first is an inefficient frameshift between two overlapping tail genes, and both the shifted and unshifted products have essential roles as chaperones of tail assembly. This class is remarkable for the widespread conservation of a frameshift mechanism in the absence of conservation of the direction or magnitude of the shift. The second class of frameshifts adds an Ig-like domain to the C-terminus of one of the major structural proteins of the virion. In addition to the cases using a frameshift, some major structural proteins have a C-terminal Ig-like domain encoded directly in their gene, and some are missing such a domain. Among the non-tailed phages, some of the ssRNA phages have an essential termination codon readthrough event at the end of their coat protein gene.