Transcription profiling of Arabidopsis polysomal and non-polysomal RNA samples isolated from 10-day-old wild-type and eif3h mutant plants

ABSTRACT: Microarray comparisons of polysome loading in wild-type Arabidopsis and eif3h mutant; Goal: ; To find the target mRNAs that are translationally regulated by eIF3h. BACKGROUND: The eukaryotic translation initiation factor eIF3 has multiple roles during the initiation of translation of cytoplasmic mRNAs. However, the contributions of individual subunits of eIF3 to the translation of specific mRNAs remain poorly understood. RESULTS: Working with stable reporter transgenes in Arabidopsis thaliana it was demonstrated that the h subunit of; eIF3 contributes to the efficient translation initiation of mRNAs harboring upstream open reading frames (uORFs) in their 5’ leader sequence. uORFs, which can function as devices for translational regulation, are present in over 30% of Arabidopsis mRNAs, and are enriched among mRNAs for transcriptional regulators and protein modifying enzymes. Microarray comparisons of polysome loading in wild-type and eif3h mutant plants revealed that eIF3h generally helps to maintain efficient polysome loading of mRNAs harboring multiple uORFs. Independently, eIF3h also boosted polysome loading of mRNAs with long coding sequences. Moreover, the lesion in eIF3h revealed a concerted upregulation of translation for specific functional subgroups of mRNAs, including ribosomal proteins and proteins involved in photosynthesis. CONCLUSIONS: The intact eIF3h protein contributes to efficient translation initiation on 5’ leader sequences harboring multiple uORFs, although mRNA features independent of uORFs were also implicated. Moreover, our data suggest that regulons of translational control can be revealed by mutations in generic translation initiation factors. Experiment Overall Design: Polysomal and non-polysomal RNA samples were isolated from 10-day-old wild-type and eif3h mutant plants. The translation state (ratio between the polysome and non-polysome, PL/NP) for each gene in the WT and in the mutant was separately established, and then the translation states between the genotype were compared.

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Albrecht von Arnim 

PROVIDER: E-GEOD-6024 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress