title: Analysis of two human pre-ribosomal factors, bystin and hTsr1, highlights differences in evolution of ribosome biogenesis between yeast and mammals.
abstract: Recent studies reveal that maturation of the 40S ribosomal subunit precursors in mammals includes an additional step during processing of the internal transcribed spacer 1 (ITS1), when compared with yeast Saccharomyces cerevisiae, even though the protein content of the pre-40S particle appears to be the same. Here, we examine by depletion with siRNA treatment the function of human orthologs of two essential yeast pre-ribosomal factors, hEnp1/bystin and hTsr1. Like their yeast orthologs, bystin is required for efficient cleavage of the ITS1 and further processing of this domain within the pre-40S particles, whereas hTsr1 is necessary for the final maturation steps. However, bystin depletion leads to accumulation of an unusual 18S rRNA precursor, revealing a new step in ITS1 processing that potentially involves an exonuclease. In addition, pre-40S particles lacking hTsr1 are partially retained in the nucleus, whereas depletion of Tsr1p in yeast results in strong cytoplasmic accumulation of pre-40S particles. These data indicate that ITS1 processing in human cells may be more complex than currently envisioned and that coordination between maturation and nuclear export of pre-40S particles has evolved differently in yeast and mammalian cells.
authors.affiliation: Université de Toulouse, UPS, Laboratoire de Biologie Moléculaire Eucaryote and CNRS, LBME, F-31000 Toulouse, France.
authors.forename: Coralie
authors.initials: C
authors.lastname: Carron
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: O'Donohue
authors.forename: Valérie
authors.initials: V
authors.lastname: Choesmel
authors.forename: Marlène
authors.initials: M
authors.lastname: Faubladier
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Gleizes
mesh_terms: D021581:Active Transport, Cell Nucleus; D005075:Biological Evolution; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000737:chemistry; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D054682:Ribosome Subunits, Small, Eukaryotic / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
chemical_list: C112245:BYSL protein, human; D015815:Cell Adhesion Molecules; C104527:ENP1 protein, S cerevisiae; D009687:Nuclear Proteins; D012322:RNA Precursors; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C555735:Tsr1 protein, human
references.citation: J Biol Chem. 1973 Feb 25;248(4):1412-6
references.pmid: 4568815
references.citation: Trends Cell Biol. 2003 May;13(5):255-63
references.pmid: 12742169
references.citation: Biochem J. 2002 Jun 15;364(Pt 3):669-77
references.pmid: 12049630
references.citation: PLoS Biol. 2009 Oct;7(10):e1000213
references.pmid: 19806183
references.citation: J Biol Chem. 2005 Nov 18;280(46):38177-85
references.pmid: 16159874
references.citation: Cell. 2002 Apr 19;109(2):145-8
references.pmid: 12007400
references.citation: Nature. 2002 Jun 27;417(6892):967-70
references.pmid: 12068309
references.citation: Mol Cell. 2007 Apr 13;26(1):51-62
references.pmid: 17434126
references.citation: EMBO J. 2005 Aug 17;24(16):2862-72
references.pmid: 16037817
references.citation: FEBS Lett. 2006 Nov 13;580(26):6062-8
references.pmid: 17055491
references.citation: Mol Cell Biol. 2007 Mar;27(6):2202-14
references.pmid: 17242206
references.citation: Genes Dev. 1995 Oct 15;9(20):2470-81
references.pmid: 7590228
references.citation: Mol Cell Biol. 2003 Mar;23(6):2083-95
references.pmid: 12612080
references.citation: J Cell Biol. 2009 Jun 29;185(7):1167-80
references.pmid: 19564402
references.citation: Mol Cell Biol. 2003 Mar;23(5):1798-807
references.pmid: 12588997
references.citation: Gene. 2003 Aug 14;313:17-42
references.pmid: 12957375
references.citation: EMBO J. 2002 Oct 15;21(20):5539-47
references.pmid: 12374754
references.citation: Curr Opin Cell Biol. 2002 Jun;14(3):313-8
references.pmid: 12067653
references.citation: Blood Cells Mol Dis. 2007 Jul-Aug;39(1):35-43
references.pmid: 17376718
references.citation: Cell Res. 2009 Oct;19(10):1150-64
references.pmid: 19687802
references.citation: Prog Nucleic Acid Res Mol Biol. 1994;49:197-239
references.pmid: 7863007
references.citation: J Cell Biol. 2010 Sep 6;190(5):853-66
references.pmid: 20819938
references.citation: Hum Mol Genet. 2008 May 1;17(9):1253-63
references.pmid: 18230666
references.citation: Nucleic Acids Res. 2003 Jan 15;31(2):690-9
references.pmid: 12527778
references.citation: Biol Reprod. 1999 Mar;60(3):621-7
references.pmid: 10026108
references.citation: Mol Biol Cell. 2000 Aug;11(8):2705-17
references.pmid: 10930464
references.citation: Proc Natl Acad Sci U S A. 1998 Apr 28;95(9):5027-32
references.pmid: 9560222
references.citation: RNA. 2001 Sep;7(9):1254-67
references.pmid: 11565748
references.citation: Mol Cell Biol. 2003 Jul;23(13):4449-60
references.pmid: 12808088
references.citation: Mol Cell Biol. 2010 Feb;30(4):976-84
references.pmid: 20008552
references.citation: Exp Cell Res. 2004 May 15;296(1):43-50
references.pmid: 15120992
references.citation: EMBO J. 2004 Jun 16;23(12):2336-47
references.pmid: 15167894
references.citation: Genetics. 2006 Oct;174(2):679-91
references.pmid: 16888326
references.citation: Mol Cell. 2002 Jul;10(1):105-15
references.pmid: 12150911
references.citation: EMBO J. 2001 Aug 1;20(15):4204-13
references.pmid: 11483523
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14259-64
references.pmid: 19706509
references.citation: Biochem J. 2007 Jun 15;404(3):373-81
references.pmid: 17381424
references.citation: RNA. 2001 Sep;7(9):1268-83
references.pmid: 11565749
references.citation: Annu Rev Genet. 1999;33:261-311
references.pmid: 10690410
references.citation: RNA. 2004 Nov;10(11):1698-701
references.pmid: 15388878
references.citation: Nature. 2006 Jun 1;441(7093):651-5
references.pmid: 16738661
references.citation: EMBO J. 1993 Jul;12(7):2913-20
references.pmid: 8335005
references.citation: Prog Nucleic Acid Res Mol Biol. 1990;39:241-303
references.pmid: 2247610
references.citation: Genes Dev. 2004 Jan 15;18(2):196-209
references.pmid: 14729571
references.citation: Blood. 2007 Feb 1;109(3):1275-83
references.pmid: 17053056
references.citation: EMBO J. 2003 Mar 17;22(6):1370-80
references.pmid: 12628929
references.citation: Nucleic Acids Res. 2003 Feb 1;31(3):799-804
references.pmid: 12560474
references.citation: J Biol Chem. 2009 Dec 11;284(50):35079-91
references.pmid: 19801658