Fig. 5. Effects of 5′ and 3′ deletions (relative to the frameshift site) on the +1 frameshifting efficiency of SPA. The constructs were transformed in Δspa::LEU2 ura4-D18 leu1-32 ade6-M216 h– strain (high polyamine levels). (A) 5′ deletion data. Numbers on the x-axis indicate SPA ORF1 sense codons left [wild type (WT) = 66 codons left]. (B) 3′ deletion data. x-axis numbers indicate nucleotides left 3′ of the frameshift site (WT = 180 nucleotides left). * marks constructs for which in-frames were not made. In these cases frameshifting was calculated relative to the closest available in-frame construct. (C) Graphical representation of the deletion data in which the deletions are shown to scale relative to the coding region of SPA (ORF1 + ORF2). The position and size of the WT standard is also depicted. The frameshift site is indicated by an arrow.