Project description:Long oligonucleotide microarrays were used for the study of expression profile changes during seedling photomorphogenesis in rice and in Arabidopsis. Different light quality treatments were applied to seedlings. To dissect organ-specific light effects, we further profiled shoot and root organs in both species. Keywords = rice Keywords = Arabidopsis Keywords = photomorphogenesis Keywords: ordered
Project description:Long oligonucleotide microarrays were used for the study of expression profile changes during seedling photomorphogenesis in rice and in Arabidopsis. Different light quality treatments were applied to seedlings. To dissect organ-specific light effects, we further profiled shoot and root organs in both species. Keywords = rice Keywords = Arabidopsis Keywords = photomorphogenesis Keywords: ordered
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: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:Arabidopsis seedlings undergo photomorphogenic development even in darkness when the function of De-etiolated 1 (DET1), a repressor of photomorphogenesis, is disrupted. Our results indicate that DET1 directly interacts with a group of transcription factors known as the phytochrome-interacting factors (PIFs). Furthermore, our results suggest that DET1 positively regulates PIF protein levels primarily by stabilizing PIF proteins in the dark. Genomic analysis also revealed that DET1 may control the expression of light-regulated genes to mediate photomorphogenesis partially through PIFs.
Project description:Light-induced phosphorylation is necessary and essential for the degradation of phytochrome-interacting factors (PIFs), the central repressors of photomorphogenesis. Although the kinases responsible for PIF phosphorylation have been extensively studied, the phosphatases underlying PIF dephosphorylation are largely unknown. Here, we real that mutation of FyPP1 and FyPP3, two catalytic subunits of PP6 phosphatases, promoted photomorphogenesis of seedlings in the dark. PP6 and PIFs functioned synergistically to repress photomorphogenesis. FyPP1 and FyPP3 directly interacted with and dephosphorylated PIF3 and PIF4. The light-induced degradation of PIF4 and the PIF transcriptional activities were dependent on PP6 activity. These data demonstrate that PP6 phosphatases repress photomorphogenesis through regulation of PIF phosphorylation, protein stability and transcriptional activity.
Project description:Arabidopsis seedlings undergo photomorphogenic development even in darkness when the function of De-etiolated 1 (DET1), a repressor of photomorphogenesis, is disrupted. Our results indicate that DET1 directly interacts with a group of transcription factors known as the phytochrome-interacting factors (PIFs). Furthermore, our results suggest that DET1 positively regulates PIF protein levels primarily by stabilizing PIF proteins in the dark. Genomic analysis also revealed that DET1 may control the expression of light-regulated genes to mediate photomorphogenesis partially through PIFs. Total of twelve samples, two treatments and three genotypes, and each have three replicates.
Project description:Cryptochromes (CRYs) is known as the key blue light receptors that promote photomorphogenesis in Arabidopsis, but to date, the underlying mechanisms are still not fully understood. Through interrogating the CRY2 interactome, we identified MOS4-ASSOCIATED COMPLEX subunits 3A and 3B (MAC3A and MAC3B) as blue light-independent CRY2 interacting partners. MAC3A/B proteins could be assembled into liquid nuclear condensates of CRYs in a blue light-dependent manner. Hypocotyl elongation is markedly repressed in mac3ab double knock-out mutants under various light conditions, which uncovers a previously unknown role of MAC3A/B as negative regulators in plant photomorphogenesis. Our results also uncover the noncanonical activities of MAC3A as the DNA-binding proteins that regulate transcription. Genome-wide mapping of MAC3A-binding sites reveals that blue light facilitates the binding of MAC3A to its targets, which is weakened in cry1cry2 mutants, suggesting that CRYs may enhance MAC3A activities in blue light to negatively influence photomorphogenesis. Interestingly, we observe that the genomic binding sites of MAC3A and HY5 are largely overlapped, and physical interactions between MAC3A and HY5 are detected as well. In addition, the in vitro DNA-binding assay shows that both proteins compete for the same DNA probe. These results indicate that MAC3A may antagonize the function of HY5 by competing for the common binding sites across the genome. Taken together, we propose that cryptochromes may fine-tune Arabidopsis photomorphogenesis by balancing the positive and negative effects on HY5 activities.
Project description:Comparison of the binding of GOLDEN2-LIKE (GLK) transcription factors in tomato, tobacco, Arabidopsis, maize and rice, show that genome cis-variation caused wide-spread TF binding divergence, and most of the TF binding sites are genetically redundant.