Figure 1. An outline of the mRNA-tagging technique.  A. A schematic of myo-3p::flag::pab-1. The initiator methionine and stop codon are shown.  The dark blue boxes show the predicted pab-1 exons (underlined and labeled), the white boxes show UTRs, and the light blue box represents the FLAG-tag.  B. A schematic of the muscle mRNA-tagging strain. The myo-3p drives the expression of FLAG::PAB-1 in non-pharyngeal muscle cells (red), but in no other cells, such as the intestine (gray).  Thus, FLAG::PAB-1 (blue) only binds to muscle-expressed mRNAs, while the endogenous PAB-1 (white) binds all mRNAs.  Upon mRNA/FLAG::PAB-1 co-immunoprecipitation, only muscle-expressed mRNAs are isolated. The nucleus is shown as a black circle.