−1 Frameshifting at a CGA AAG Hexanucleotide Site Is Required for Transposition of Insertion Sequence IS 1222

Abstract
The discovery of programmed −1 frameshifting at the hexanucleotide shift site CGA_AAG, in addition to the classical X_XXY_YYZ heptanucleotide shift sequences, prompted a search for instances among eubacterial insertion sequence elements. IS 1222 has a CGA_AAG shift site. A genetic analysis revealed that frameshifting at this site is required for transposition.