Open AccessThe Splicing ATPase Prp43p Is a Component of Multiple Preribosomal Particles
Author(s) -
Simon Lebaron,
Carine Froment,
Micheline FromontRacine,
Jean-Christophe Rain,
Bernard Monsarrat,
Michèle CaizerguesFerrer,
Y. Henry
Publication year - 2005
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.25.21.9269-9282.2005
Subject(s) - biology , nucleolus , rna splicing , ribosomal rna , intron , spliceosome , rna polymerase i , ribosome biogenesis , ribosome , microbiology and biotechnology , rna helicase a , rna polymerase iii , transcription (linguistics) , rna , helicase , genetics , cytoplasm , gene , rna polymerase , linguistics , philosophy
Prp43pis a putative helicase of the DEAH family which is required for therelease of the lariat intron from the spliceosome. Prp43p could alsoplay a role in ribosome synthesis, since it accumulates in thenucleolus. Consistent with this hypothesis, we find that depletion ofPrp43p leads to accumulation of 35S pre-rRNA and strongly reduceslevels of all downstream pre-rRNA processing intermediates. As aresult, the steady-state levels of mature rRNAs are greatly diminishedfollowing Prp43p depletion. We present data arguing that such effectsare unlikely to be solely due to splicing defects. Moreover, wedemonstrate by a combination of a comprehensive two-hybrid screen,tandem-affinity purification followed by mass spectrometry, andNorthern analyses that Prp43p is associated with 90S, pre-60S, andpre-40S ribosomal particles. Prp43p seems preferentially associatedwith Pfa1p, a novel specific component of pre-40S ribosomal particles.In addition, Prp43p interacts with components of the RNA polymerase I(Pol I) transcription machinery and with mature 18S and 25S rRNAs.Hence, Prp43p might be delivered to nascent 90S ribosomal particlesduring pre-rRNA transcription and remain associated with preribosomalparticles until their final maturation steps in the cytoplasm. Our dataalso suggest that the ATPase activity of Prp43p is required for earlysteps of pre-rRNA processing and normal accumulation of maturerRNAs.