Sen34p depletion blocks tRNA splicing in vivo and delays rRNA processing.
Tif6p (eIF6) is necessary for 60S biogenesis, rRNA maturation and must be released from 60S to permit 80S assembly and translation. We characterized Tif6p interactors. Tif6p is mostly on 66S-60S pre-ribosomes, partly free. Tif6p complex(es) contain nucleo-ribosomal factors and Asc1p. Surprisingly, Tif6p particle contains the low-abundance endonuclease Sen34p. We analyzed Sen34p role on rRNA/tRNA synthesis, in vivo. Sen34p depletion impairs tRNA splicing and causes unexpected 80S accumulation. Accordingly, Sen34p overexpression causes 80S decrease and increased polysomes which suggest increased translational efficiency. With delayed kinetics, Sen34p depletion impairs rRNA processing. We conclude that Sen34p is absolutely required for tRNA splicing and that it is a rate-limiting element for efficient translation. Finally, we confirm that Tif6p accompanies 27S pre-rRNA maturation to 25S rRNA and we suggest that Sen34p endonuclease in Tif6p complex may affect also rRNA maturation.
Volta
Viviana
V
Molecular Histology and Cell Growth, DIBIT-HSR, 20132 Milan, Italy.
Ceci
Marcello
M
Emery
Bertrand
B
Bachi
Angela
A
Petfalski
Elisabeth
E
Tollervey
David
D
Linder
Patrick
P
Marchisio
Pier Carlo
PC
Piatti
Simonetta
S
Biffo
Stefano
S
D002352:Carrier Proteins / Q000378:metabolism; D004722:Endoribonucleases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D007381:Intermediate Filament Proteins / Q000378:metabolism; D007700:Kinetics; D010750:Phosphoproteins / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012326:RNA Splicing; D012335:RNA, Ribosomal / Q000378:metabolism*; D012343:RNA, Transfer / Q000096:biosynthesis / Q000378:metabolism*; D012269:Ribosomal Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D002352:Carrier Proteins; D007381:Intermediate Filament Proteins; D010750:Phosphoproteins; D012322:RNA Precursors; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C491609:TIF6 protein, S cerevisiae; D012343:RNA, Transfer; D004722:Endoribonucleases; C505245:Sen34 protein, S cerevisiae