The RNA-binding protein La is found in most eukaryotes, and despite being essential in many organisms, its function is not completely clear. Trypanosoma brucei, the causative agent of human African trypanosomiasis, encodes a 'classical' La protein (TbLa) composed of a La-motif, two RNA recognition motifs (RRM1 and RRM2α), a C-terminal short basic motif (SBM), and a nuclear localization signal (NLS). In T. brucei, like in most eukaryotes, position 34 of tRNATyr, -Asp, -Asn and -His is modified with queuosine (Q34). The steady-state levels of queuosine-modified tRNA in the insect form (procyclic) of T. brucei can fluctuate dynamically depending on growth conditions, but the mechanism(s) controlling Q34 levels are not well understood. A well-established function of La is in precursor-tRNA 3'-end metabolism, but in this work, we demonstrate that La also controls Q34-tRNA levels. Individual domain deletions showed that while deletion of La motif or RRM1 causes dysregulation of Q34-tRNA levels, no other domain plays a similar role. We also show that La is important for the normal balance of several additional tRNA modifications. These findings are discussed in the context of substrate competition between La and modification enzymes, also highlighting subcellular localization as a key determinant of tRNA function.

• MeSH
• nukleosid Q metabolismus   analogy a deriváty   MeSH
• posttranskripční úpravy RNA * MeSH
• proteinové domény MeSH
• proteiny vázající RNA * metabolismus   chemie   genetika   MeSH
• protozoální proteiny * metabolismus   chemie   genetika   MeSH
• RNA transferová * metabolismus   genetika   MeSH
• Trypanosoma brucei brucei * genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• nukleosid Q MeSH
• proteiny vázající RNA * MeSH
• protozoální proteiny * MeSH
• RNA transferová * MeSH