The expression of sup-7 tRNA is influenced by the promoter of the host gene, C03B1.2.

The read-through reporter strain (RRS) or N2 worms were injected with the indicated constructs (the construct number corresponds to its number in Fig 5). We screened all the progeny for either red fluorescence (indicating sup-7 expression) or for the presence of the corresponding co-injection marker. Viable lines that express the sup-7 tryptophan tRNAs ("sup-7 (+) promoter") were obtained by cultivating the injected worms at 22°C. Worms that were injected with the "sup-7 (+) HSP" promoter were cultivated at 15°C.