Validation of the REEact1 and control S. pombe strains. (A) Schematic of the PCR products and their sizes for the act1, ubi4-MEEEact1, and ubi-REEact1 strains using the same pair of primers for genotyping and 1% agarose gel image of the PCR products of the different strains using the genotyping primers. Note the presence of a single band of the expected sizes for all the strains. (B) Sequence alignment results for the four ubi4 strains as compared with their respective expected sequences as derived from SnapGene software. (C) Western blot using an anti-actin antibody for the four Ubi4 strains. The actin bands are at the expected size of ∼42 kD of the actin product after Ubi4 tag cleavage. Also note the differences in migration of actin between the MEEE and REE strains (D) (i) MS/MS spectrum for an MEEE peptide from the MEEE (wt) strain. (ii) MS/MS spectrum for an REE peptide from the REE (wt) strain. (iii) Table of the number of MEEE or REE peptides observed for the different strains. Source data are available for this figure: SourceData FS4.