Distinct functions of maternal and somatic Pat1 protein paralogs.
We previously identified Xenopus Pat1a (P100) as a member of the maternal CPEB RNP complex, whose components resemble those of P-(rocessing) bodies, and which is implicated in translational control in Xenopus oocytes. Database searches have identified Pat1a proteins in other vertebrates, as well as paralogous Pat1b proteins. Here we characterize Pat1 proteins, which have no readily discernable sequence features, in Xenopus oocytes, eggs, and early embryos and in human tissue culture cells. xPat1a and 1b have essentially mutually exclusive expression patterns in oogenesis and embryogenesis. xPat1a is degraded during meiotic maturation, via PEST-like regions, while xPat1b mRNA is translationally activated at GVBD by cytoplasmic polyadenylation. Pat1 proteins bind RNA in vitro, via a central domain, with a preference for G-rich sequences, including the NRAS 5' UTR G-quadruplex-forming sequence. When tethered to reporter mRNA, both Pat proteins repress translation in oocytes. Indeed, both epitope-tagged proteins interact with the same components of the CPEB RNP complex, including CPEB, Xp54, eIF4E1b, Rap55B, and ePAB. However, examining endogenous protein interactions, we find that in oocytes only xPat1a is a bona fide component of the CPEB RNP, and that xPat1b resides in a separate large complex. In tissue culture cells, hPat1b localizes to P-bodies, while mPat1a-GFP is either found weakly in P-bodies or disperses P-bodies in a dominant-negative fashion. Altogether we conclude that Pat1a and Pat1b proteins have distinct functions, mediated in separate complexes. Pat1a is a translational repressor in oocytes in a CPEB-containing complex, and Pat1b is a component of P-bodies in somatic cells.
Marnef
Aline
A
Department of Biochemistry, University of Cambridge, Cambridge CB21QW, United Kingdom.
Maldonado
Maria
M
Bugaut
Anthony
A
Balasubramanian
Shankar
S
Kress
Michel
M
Weil
Dominique
D
Standart
Nancy
N
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D051379:Mice; D009865:Oocytes / Q000378:metabolism*; D010802:Phylogeny; D011485:Protein Binding; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; C553601:PATL1 protein, Xenopus; C526510:PATL1 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029867:Xenopus Proteins; C075198:PATL2 protein, Xenopus; D012313:RNA
RNA. 2001 Jun;7(6):875-86
11424938
J Cell Biol. 2008 Aug 11;182(3):543-57
18695045
PLoS Biol. 2006 Jul;4(7):e210
16756390
Mol Biol Cell. 2009 Jan;20(1):176-87
18923137
J Biol Chem. 2004 Jun 4;279(23):24323-33
15044472
EMBO J. 2009 Feb 4;28(3):213-22
19131968
Cell. 2005 Sep 23;122(6):875-86
16179257
Genes Dev. 2001 Mar 15;15(6):774-88
11274061
Dev Biol. 2008 Nov 1;323(1):76-87
18692039
Mol Biol Cell. 2009 May;20(9):2464-72
19297524
Mol Cell Biol. 1998 Oct;18(10):6152-63
9742132
Biochem Soc Trans. 2010 Dec;38(6):1602-7
21118134
Genes Dev. 1994 Apr 15;8(8):926-38
7926777
EMBO J. 2000 Sep 1;19(17):4723-33
10970864
Mol Cell Biol. 2000 May;20(10):3538-49
10779343
Cell. 2001 Nov 16;107(4):489-99
11719189
J Cell Biol. 2007 Nov 5;179(3):437-49
17984320
Nat Chem Biol. 2007 Apr;3(4):218-21
17322877
Retrovirology. 2009 Mar 09;6:26
19272132
J Cell Biol. 2004 Apr;165(1):31-40
15067023
Mol Cell. 2009 Sep 24;35(6):868-80
19716330
RNA. 2001 Dec;7(12):1728-42
11780630
Trends Biochem Sci. 2007 Jun;32(6):279-85
17481902
Mol Cell Biol. 1998 Feb;18(2):685-93
9447964
Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2647-52
16477042
Mol Cell. 2007 Mar 9;25(5):635-46
17349952
Mol Cell Biol. 2009 Dec;29(23):6220-31
19797087
Cell. 2006 Jun 16;125(6):1111-24
16777601
J Cell Biol. 2010 Apr 19;189(2):289-302
20404111
Biochemistry. 2006 Jul 11;45(27):8319-30
16819831
Mol Cell Biol. 2008 Feb;28(4):1298-312
18086885
Cell. 2009 Feb 20;136(4):731-45
19239892
Mol Cell. 2009 Jun 26;34(6):696-709
19560422
Dev Biol. 2001 Mar 15;231(2):447-58
11237472
Eur J Biochem. 1992 Jun 15;206(3):673-83
1606954
Methods. 2010 May;51(1):165-9
20188836
Trends Biochem Sci. 1996 Jul;21(7):267-71
8755249
Biol Reprod. 2010 May;82(5):1008-17
20075394
Cell Host Microbe. 2008 Apr 17;3(4):206-12
18407064
Dev Biol. 2010 Aug 1;344(1):272-83
20471969
Biochem J. 2003 Feb 15;370(Pt 1):91-100
12401129
EMBO J. 2010 Jul 21;29(14):2368-80
20543818
J Biol Chem. 2007 Dec 28;282(52):37389-401
17942399
J Biol Chem. 2006 Dec 29;281(52):40096-106
17074753
J Cell Biol. 2008 Aug 11;182(3):559-72
18695046
J Cell Sci. 2007 Mar 15;120(Pt 6):1081-92
17327273
Biochim Biophys Acta. 2007 Dec;1773(12):1786-92
17936923
Nucleic Acids Res. 2004 Feb 24;32(4):1325-34
14982957
Genetics. 2009 Jan;181(1):93-103
19015546
PLoS One. 2009 Aug 27;4(8):e6783
19710908
Methods Enzymol. 1983;96:50-74
6656641
RNA. 2009 Jul;15(7):1265-73
19474145
Mol Cell Biol. 2010 Sep;30(17):4308-23
20584987
Mol Biol Cell. 2009 Dec;20(23):4951-61
19812249
Nucleic Acids Res. 2007;35(14):4715-27
17604308
J Cell Sci. 2005 Mar 1;118(Pt 5):981-92
15731006
Biochim Biophys Acta. 2008 Apr;1779(4):217-29
18316045
Methods Enzymol. 2007;431:61-81
17923231
Genes Dev. 2007 Oct 15;21(20):2558-70
17901217
EMBO J. 2000 Apr 3;19(7):1661-71
10747033
Biochem Soc Trans. 2008 Aug;36(Pt 4):671-6
18631138
Nature. 2000 Mar 30;404(6777):515-8
10761922
Nat Rev Mol Cell Biol. 2010 Feb;11(2):113-27
20094052
Nat Rev Mol Cell Biol. 2007 Jan;8(1):9-22
17183357
RNA. 2007 Apr;13(4):493-502
17307817
RNA. 2005 Dec;11(12):1795-802
16314453
EMBO J. 2001 Sep 3;20(17):4803-13
11532944
Mol Cell Biol. 2007 Jun;27(11):3970-81
17403906
Methods. 1999 Jan;17(1):46-51
10075882