Ectopic 5' splice sites inhibit gene expression by engaging RNA surveillance and silencing pathways in plants.
The quality control of mRNA maturation is a highly regulated process that surveys pre-mRNA integrity and eliminates improperly matured pre-mRNAs. In nature, certain viruses regulate the expression of their genes by hijacking the endogenous RNA quality control machinery. We demonstrate that the inclusion of 5' splice sites within the 3'-untranslated region of a reporter gene in plants alters the pre-mRNA cleavage and polyadenylation process, resulting in pre-mRNA degradation, exemplifying a regulatory mechanism conserved between kingdoms. Altered pre-mRNA processing was associated with an inhibition of homologous gene expression in trans and the preferential accumulation of 24-nucleotide (nt) short-interfering RNAs (siRNAs) as opposed to 21-nt siRNA subspecies, suggesting that degradation of the aberrant pre-mRNA involves the silencing machinery. However, gene expression was not restored by coexpression of a silencing suppressor or in an RNA-dependent RNA polymerase (RDR6)-deficient background despite reduced 24-nt siRNA accumulation. Our data highlight a complex cross talk between the quality control RNA machinery, 3'-end pre-mRNA maturation, and RNA-silencing pathways capable of discriminating among different types of aberrant RNAs.
Wypijewski
Krzysztof
K
Plant Pathology Department, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom.
Hornyik
Csaba
C
Shaw
Jane A
JA
Stephens
Jennifer
J
Goraczniak
Rafal
R
Gunderson
Samuel I
SI
Lacomme
Christophe
C
D020413:3' Untranslated Regions / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016254:Mutagenesis, Insertional; D009690:Nucleic Acid Conformation; D026723:Polyadenylation; D034622:RNA Interference; D022821:RNA Splice Sites / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000737:chemistry / Q000378:metabolism; D013489:Suppression, Genetic; D014026:Nicotiana / Q000235:genetics*; D017864:Tombusvirus / Q000235:genetics
D020413:3' Untranslated Regions; D022821:RNA Splice Sites; D012333:RNA, Messenger; D018749:RNA, Plant; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins