Project description:The environmental “light” plays a vital role in regulating the plant growth and development. Transcriptomic profilings were widely used to examine how light regulates the changes of mRNA populations at a genome-wide scale. However, it remains unclear if translational regulation represents a new dimension of gene expression regulation in response to the light signal. Through a transcriptomic comparison of steady-state and polysome-bound mRNAs, we revealed an increased translational efficiency in de-etiolating Arabidopsis seedlings. Over 3,500 genes are subjected to translational regulation whereas only about 770 genes have increased mRNA abundances in response to the light signal. This result suggests a stronger impact of translational control over transcriptomic changes during photomorphogenesis. Genes encoding ribosomal protein are preferentially regulated at the translational level, possibly contributing to the enhancement of translation efficiency as observed. We also uncovered mRNAs regulated at the translational level share characteristics of longer half-lives and shorter cDNA length. The presence of a cis-element, TAGGGTTT, in the 5’untranslated region of a transcript renders its translational regulation by light signals. Taken together, our study revealed a previously neglected aspect of gene expression regulation during Arabidopsis photomorphogenesis. The identities and molecular signatures associated with mRNAs regulated at the translational level also offer new directions to perform mechanistic studies of light-trigged translational enhancement in Arabidopsis. Three biological replicates for 4-d-old etiolated seedlings with or without 0. 5 h or 4 h of white-light treatment.
Project description:The environmental “light” plays a vital role in regulating the plant growth and development. Transcriptomic profilings were widely used to examine how light regulates the changes of mRNA populations at a genome-wide scale. However, it remains unclear if translational regulation represents a new dimension of gene expression regulation in response to the light signal. Through a transcriptomic comparison of steady-state and polysome-bound mRNAs, we revealed an increased translational efficiency in de-etiolating Arabidopsis seedlings. Over 3,500 genes are subjected to translational regulation whereas only about 770 genes have increased mRNA abundances in response to the light signal. This result suggests a stronger impact of translational control over transcriptomic changes during photomorphogenesis. Genes encoding ribosomal protein are preferentially regulated at the translational level, possibly contributing to the enhancement of translation efficiency as observed. We also uncovered mRNAs regulated at the translational level share characteristics of longer half-lives and shorter cDNA length. The presence of a cis-element, TAGGGTTT, in the 5’untranslated region of a transcript renders its translational regulation by light signals. Taken together, our study revealed a previously neglected aspect of gene expression regulation during Arabidopsis photomorphogenesis. The identities and molecular signatures associated with mRNAs regulated at the translational level also offer new directions to perform mechanistic studies of light-trigged translational enhancement in Arabidopsis.
Project description:Small RNA-mediated post-transcriptional control of gene expression is critical for the growth and development of plants. Previous investigations on Arabidopsis suggest that photomorphogenesis may be regulated by the action of sRNAs. However, current information on sRNAs and their regulation of target genes during photomorphogenesis remain mostly unknown. We aim to provide a more systemic view on sRNA-controlled gene expression in this developmental process. We have found that, in addition to microRNAs (miRNAs) and phased small interfering RNAs (phasiRNAs), other siRNAs may also act as regulators of the de-etiolating process. In addition, we have discovered several miRNA-target pairs that act as new players of photomorphogenesis.
Project description:DELLA proteins act as hubs that relay environmental information to the multiple transcriptional circuits that control growth and development through physical interaction with transcription factors from different families. We have analyzed the presence of one DELLA protein at the Arabidopsis genome by chromatin immunoprecipitation coupled to large-scale sequencing and we find that it binds at the promoters of multiple genes. Enrichment analysis shows a strong preference for cis elements recognized by specific transcription factor families. In particular, we demonstrate that DELLA proteins are recruited by type-B ARABIDOPSIS RESPONSE REGULATORS (ARR) to the promoters of cytokinin-regulated genes, where they act as transcriptional co-activators. The biological relevance of this mechanism is underpinned by the necessity of simultaneous presence of DELLAs and ARRs to restrict root meristem growth and to promote photomorphogenesis.
Project description:DELLA proteins act as hubs that relay environmental information to the multiple transcriptional circuits that control growth and development through physical interaction with transcription factors from different families. We have analyzed the presence of one DELLA protein at the Arabidopsis genome by chromatin immunoprecipitation coupled to large-scale sequencing and we find that it binds at the promoters of multiple genes. Enrichment analysis shows a strong preference for cis elements recognized by specific transcription factor families. In particular, we demonstrate that DELLA proteins are recruited by type-B ARABIDOPSIS RESPONSE REGULATORS (ARR) to the promoters of cytokinin-regulated genes, where they act as transcriptional co-activators. The biological relevance of this mechanism is underpinned by the necessity of simultaneous presence of DELLAs and ARRs to restrict root meristem growth and to promote photomorphogenesis. Provided are 3 biological replicates analysing RGA binding sites in Arabidopsis seedlings. ChIP-seq was performed on plants expressing RGA-GFP under the native RGA promoter and on non-transgenic control plants as reference
Project description:Selective mRNA sequestration by OLIGOURIDYLATE BINDING PROTEIN 1 contributes to translational control during hypoxia in Arabidopsis