New insights into miR398 functions in Arabidopsis.
We recently identified a new target of microRNA398 (miR398), a conserved miRNA in plants. In Arabidopsis, miR398 targets the mRNAs of two copper/zinc superoxide dismutases (Cu/Zn SODs) by triggering their cleavage or repressing their translation. We analysed the transcriptomes of mutants impaired in miR398 production, revealing that the mRNAs encoding the chaperone (CCS1), essential for copper delivering to the Cu/Zn SODs of Arabidopsis and to generate the mature proteins, were undiscovered targets of miR398. It is likely that CCS1 was not identified by previous bioinformatic predictions because of the number of mismatches between the mRNA and its target. Since CCS1 has four mismatches and one GU wobble, it would have been excluded by the majority of prediction algorithms. miR398 directs the post-transcriptional regulation of CCS1 mRNAs by cleavage and ARGONAUTE10 (AGO10)-mediated translational repression. Indeed, CCS1 protein accumulate in zwille (ago10) mutants while both miR398 and CCS1 mRNAs levels remain identical to the Landsberg erecta WT plants. Moreover, since AGO10 is a negative regulator of AGO1, the CCS1 protein is more abundant in a double ago1-27 ago10-3 Col mutant compared to the single hypomorphic ago1-27 mutant, as previously shown for CSD2.
Bouché
Nicolas
N
Institut Jean Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRA Centre de Versailles-Grignon, Versailles, France. bouche@versailles.inra.fr
Plant Cell. 2002 Mar;14(3):629-39
11910010
Mol Cell. 2004 Jun 18;14(6):787-99
15200956
Plant Cell. 2004 Aug;16(8):2001-19
15258262
Plant Mol Biol. 2008 Jul;67(4):403-17
18392778
Planta. 2009 Mar;229(4):1009-14
19148671
PLoS Genet. 2009 Sep;5(9):e1000646
19763164
Science. 2008 May 30;320(5880):1185-90
18483398
Plant J. 2010 May;62(3):454-62
20128885
Planta. 2010 Feb;231(3):705-16
20012085
EMBO J. 1998 Mar 16;17(6):1799-809
9501101
Plant Physiol. 2005 Sep;139(1):425-36
16126858
Plant Cell. 2006 Aug;18(8):2051-65
16861386
FEBS Lett. 2005 Apr 25;579(11):2307-12
15848163
Dev Cell. 2007 Jul;13(1):115-25
17609114
Proc Natl Acad Sci U S A. 2004 Aug 3;101(31):11511-6
15272084
Trends Plant Sci. 2008 Jul;13(7):359-67
18501664
Plant Mol Biol. 2009 Sep;71(1-2):51-9
19533381
Science. 2002 Sep 20;297(5589):2053-6
12242443
Nat Biotechnol. 2008 Aug;26(8):941-6
18542052
Trends Plant Sci. 2008 Jul;13(7):350-8
18508405