The Arabidopsis STV1 protein, responsible for translation reinitiation, is required for auxin-mediated gynoecium patterning.
Ribosomal protein L24 (RPL24) is implicated in translation reinitiation of polycistronic genes. A newly isolated Arabidopsis thaliana short valve1 (stv1) mutant, in which one of the RPL24-encoding genes, RPL24B, is deleted, shows specific defects in the apical-basal patterning of the gynoecium, in addition to phenotypes induced by ribosome deficiency. A similar gynoecium phenotype is caused by mutations in the auxin response factor (ARF) genes ETTIN (ETT) and MONOPTEROS (MP), which have upstream open reading frames (uORFs) in their 5'-transcript leader sequences. Gynoecia of a double mutant of stv1 and a weak ett mutant allele are similar to those of a strong ett allele, and transformation with a uORF-eliminated ETT construct partially suppressed the stv1 gynoecium phenotype, implying that STV1 could influence ETT translation through its uORFs. Analyses of 5'-leader-reporter gene fusions showed that the uORFs of ETT and MP negatively regulate the translation of the downstream major ORFs, indicating that translation reinitiation is an important step for the expression of these proteins. Taken together, we propose that perturbation of translation reinitiation of the ARF transcripts causes the defects in gynoecium patterning observed in the stv1 mutant.
Nishimura
Taisuke
T
Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Wada
Takuji
T
Yamamoto
Kotaro T
KT
Okada
Kiyotaka
K
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D039642:Eukaryotic Initiation Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D016366:Open Reading Frames / Q000235:genetics; D014176:Protein Biosynthesis / Q000502:physiology; D012269:Ribosomal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C109765:ETT protein, Arabidopsis; D039642:Eukaryotic Initiation Factors; D007210:Indoleacetic Acids; C111371:MONOPTEROS protein, Arabidopsis; D009687:Nuclear Proteins; D012269:Ribosomal Proteins; C510495:STV1 protein, Arabidopsis; D014157:Transcription Factors