The essential function of the Trypanosoma brucei Trl1 homolog in procyclic cells is maturation of the intron-containing tRNA^Tyr

Effects of TbTrl1 knockdown on tRNA^Tyr maturation. (A) The cloverleaf structure of the tRNA^Tyr of T. brucei. The 11-nt intron is shown in gray letters. The anticodon sequence is boxed. Black arrows and open circles denote the positions where the 3′-exon Tyr probe and Intron probe anneal, respectively (5′ and 3′ nucleotides are marked). (B, C) Northern blot analysis of tRNA^Tyr processing steps in wild-type (WT) and TbTrl1 RNAi strain induced (+tet) and uninduced (−tet) with tetracycline after 2 d (B) or 4 d (C) of RNAi. The positions of the intron-containing, mature tRNA^Tyr and 3′-exon–intron species signals are indicated. The asterisk (*) in panel B indicates a probable 3′-extended pre-tRNA^Tyr previously described (Schneider et al. 1993). A tRNA^Glu probe was used as control (B).