TY - JOUR
T1 - Gcn4 misregulation reveals a direct role for the evolutionary conserved EKC/KEOPS in the t 6A modification of tRNAs
AU - Daugeron, Marie Claire
AU - Lenstra, Tineke L.
AU - Frizzarin, Martina
AU - El Yacoubi, Basma
AU - Liu, Xipeng
AU - Baudin-Baillieu, Agns
AU - Lijnzaad, Philip
AU - Decourty, Laurence
AU - Saveanu, Cosmin
AU - Jacquier, Alain
AU - Holstege, Frank C.P.
AU - De Crécy-Lagard, Valérie
AU - Van Tilbeurgh, Herman
AU - Libri, Domenico
N1 - Funding Information:
Centre National pour la Recherche Scientifique (CNRS), the Agence Nationale pour la Recherche (ANR) (grant ANR-09-BLAN-0349-03 to D.L. and H.vT. and ANR-08-JCJC-0019-01 to C.S.) Netherlands Organization of Scientific Research (NWO) (grants 021.002.035, 817.02.015, 050.71.057, 911.06.009, 016.108.607 to T.L.L.) Netherlands Bioinformatics Centre (NBIC), the U.S. Department of Energy (grant no. DEFG0207ER64498 to V.deC.-L.) and by the National Institutes of Health (grant no. R01 GM70641-01 to V.deC.-L.). Fondation pour la Recherche Médicale (FRM) to X.L. Funding for open access charge: CNRS.
PY - 2011/8
Y1 - 2011/8
N2 - The EKC/KEOPS complex is universally conserved in Archaea and Eukarya and has been implicated in several cellular processes, including transcription, telomere homeostasis and genomic instability. However, the molecular function of the complex has remained elusive so far. We analyzed the transcriptome of EKC/KEOPS mutants and observed a specific profile that is highly enriched in targets of the Gcn4p transcriptional activator. GCN4 expression was found to be activated at the translational level in mutants via the defective recognition of the inhibitory upstream ORFs (uORFs) present in its leader. We show that EKC/KEOPS mutants are defective for the N6-threonylcarbamoyl adenosine modification at position 37 (t 6A37) of tRNAs decoding ANN codons, which affects initiation at the inhibitory uORFs and provokes Gcn4 de-repression. Structural modeling reveals similarities between Kae1 and bacterial enzymes involved in carbamoylation reactions analogous to t 6A37 formation, supporting a direct role for the EKC in tRNA modification. These findings are further supported by strong genetic interactions of EKC mutants with a translation initiation factor and with threonine biosynthesis genes. Overall, our data provide a novel twist to understanding the primary function of the EKC/KEOPS and its impact on several essential cellular functions like transcription and telomere homeostasis.
AB - The EKC/KEOPS complex is universally conserved in Archaea and Eukarya and has been implicated in several cellular processes, including transcription, telomere homeostasis and genomic instability. However, the molecular function of the complex has remained elusive so far. We analyzed the transcriptome of EKC/KEOPS mutants and observed a specific profile that is highly enriched in targets of the Gcn4p transcriptional activator. GCN4 expression was found to be activated at the translational level in mutants via the defective recognition of the inhibitory upstream ORFs (uORFs) present in its leader. We show that EKC/KEOPS mutants are defective for the N6-threonylcarbamoyl adenosine modification at position 37 (t 6A37) of tRNAs decoding ANN codons, which affects initiation at the inhibitory uORFs and provokes Gcn4 de-repression. Structural modeling reveals similarities between Kae1 and bacterial enzymes involved in carbamoylation reactions analogous to t 6A37 formation, supporting a direct role for the EKC in tRNA modification. These findings are further supported by strong genetic interactions of EKC mutants with a translation initiation factor and with threonine biosynthesis genes. Overall, our data provide a novel twist to understanding the primary function of the EKC/KEOPS and its impact on several essential cellular functions like transcription and telomere homeostasis.
UR - https://www.scopus.com/pages/publications/80051499296
U2 - 10.1093/nar/gkr178
DO - 10.1093/nar/gkr178
M3 - Article
C2 - 21459853
AN - SCOPUS:80051499296
SN - 0305-1048
VL - 39
SP - 6148
EP - 6160
JO - Nucleic acids research
JF - Nucleic acids research
IS - 14
ER -