Structural requirements for the synthesis of tRNATrp from Dictyostelium discoideum in yeast

Dictyostelium tRNA genes can generally be expressed in vivo in yeast. Among tested Dictyostelium tRNA genes a tRNATrp gene containing a 13 bp intron is transcribed with particularly poor apparent efficiency and the intron is not removed. Elimination of the intron from the gene increases the amount of transcription products significantly. Splicing can only occur if minimal base-pairing of the anticodon with intron sequences is possible. Accumulation of tRNA gene transcripts decreases with the inability of intron splicing. Products of neither amber (UAG) nor opal (UGA) suppressor variants of the tRNATrp gene from Dictyostelium are able to suppress corresponding non-sense mutations in defined structural yeast genes. This also holds true for suppressor tRNA gene variants with precisely deleted intron regions.