A core subunit of the RNA-processing/degrading exosome specifically influences cuticular wax biosynthesis in Arabidopsis.
The cuticle is an extracellular matrix composed of cutin polyester and waxes that covers aerial organs of land plants and protects them from environmental stresses. The Arabidopsis thaliana cer7 mutant exhibits reduced cuticular wax accumulation and contains considerably lower transcript levels of ECERIFERUM3/WAX2/YORE-YORE (CER3/WAX2/YRE), a key wax biosynthetic gene. We show here that CER7 protein is a putative 3'-5' exoribonuclease homologous to yeast Ribonuclease PH45 (RRP45p), a core subunit of the RNA processing and degrading exosome that controls the expression of CER3/WAX2/YRE. We propose that CER7 acts by degrading a specific mRNA species encoding a negative regulator of CER3/WAX2/YRE transcription. A second RRP45p homolog found in Arabidopsis, designated At RRP45a, is partially functionally redundant with CER7, and complete loss of RRP45 function in Arabidopsis is lethal. To our knowledge, CER7 is currently the only example of a core exosomal subunit specifically influencing a cellular process.
Hooker
Tanya S
TS
Department of Botany, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
Lam
Patricia
P
Zheng
Huanquan
H
Kunst
Ljerka
L
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005095:Exoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D019441:Plant Epidermis / Q000378:metabolism*; D018547:Plant Stems / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014885:Waxes / Q000378:metabolism*
D029681:Arabidopsis Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D014885:Waxes; C520842:CER7 protein, Arabidopsis; D005095:Exoribonucleases