Project description:We directed expression of BLUEJAY, JACKDAW and SCARECROW through the UAS promoter in the J0571 line and performed cell sorting followed by microarray experiments to identify differentially expressed genes.
Project description:Reversible protein phosphorylation is a post-translational modification involved in virtually all plant processes, as it mediates protein activity and signal transduction. Here, we probe dynamic protein phosphorylation during de novo shoot organogenesis in Arabidopsis thaliana. We find that application of three kinase inhibitors in various time intervals has different effects on root explants. We furthermore show that short exposures to the putative His kinase inhibitor TCSA during the initial days on shoot induction medium (SIM) are detrimental for regeneration in seven natural accessions. Investigation of ahk and ahp mutants, as well as reporter lines for shoot markers and hormone responses suggests that TCSA at least partially works by impeding cytokinin signal transduction via AHK3, AHK4, AHP2, AHP3, and AHP5. A mass spectrometry-based phosphoproteome analysis further reveals profound deregulation of Ser/Thr/Tyr phosphoproteins related to protein modification, transcriptional regulation, vesicle trafficking, organ morphogenesis, and cation transport. Among TCSA-responsive factors are prior candidates with a role in shoot apical meristem patterning, such as AGO1, BAM1, PLL5, FIP37, TOP1ALPHA, and RBR1, but also proteins involved in polar auxin transport (e.g., PIN1) and brassinosteroid signalling (e.g., BIN2). Potentially novel regeneration determinants regulated by TCSA include RD2, AT1G52780, PVA11, and AVT1C, while NAIP2, OPS, ARR1, QKY, and aquaporins exhibit differential phospholevels on control SIM.
Project description:The axolotl (<i>Ambystoma mexicanum</i>) is a caudate amphibian, which has an extraordinary ability to restore a wide variety of damaged structures by a process denominated epimorphosis. While the origin and potentiality of progenitor cells that take part during epimorphic regeneration are known to some extent, the metabolic changes experienced and their associated implications, remain unexplored. However, a circuit with a potential role as a modulator of cellular metabolism along regeneration is that formed by Lin28/let-7. In this study, we report two Lin28 paralogs and eight mature let-7 microRNAs encoded in the axolotl genome. Particularly, in the proliferative blastema stage amxLin28B is more abundant in the nuclei of blastemal cells, while the microRNAs amx-let-7c and amx-let-7a are most downregulated. Functional inhibition of Lin28 factors increase the levels of most mature let-7 microRNAs, consistent with an increment of intermediary metabolites of the Krebs cycle, and phenotypic alterations in the outgrowth of the blastema. In summary, we describe the primary components of the Lin28/let-7 circuit and their function during axolotl regeneration, acting upstream of metabolic reprogramming events.
Project description:A critical step in regeneration is recreating the cellular identities and patterns of lost organs long after embryogenesis is complete. In plants, perpetual (indeterminate) organ growth occurs in apical stem cell niches, which have been shown to re-establish quickly when damaged or removed (1,2). Here we ask whether the machinery of perpetual organ growth, stem cell activity, is needed for the phase of regeneration that leads to replenishing lost cell identities and patterning, or, whether organ re-establishment enlists a wider group of pluripotent cells. We adapt a root tip regeneration system to Arabidopsis that permits us to assess the molecular and functional recovery of specific cell fates during organ regeneration. These results suggest a rapid restoration of missing cell fate and function in advance of the recovery of stem cell activity. Surprisingly, plants with mutations that fail to maintain stem cell activity were able to re-pattern their distal tip and re-specify lost cell fates. Thus, although stem cell activity is required to resume indeterminate growth (3), our results show it is not necessary for cell re-specification and patterning steps. This implies a regeneration mechanism that coordinates patterning of the whole organ, as in embryogenesis, but is initiated from different starting morphologies. 1. Feldman, L. J. Denovo Origin of Quiescent Center Regenerating Root Apices of Zea-Mays. Planta 128, 207-212 (1976). 2. Xu, J. et al. A molecular framework for plant regeneration. Science 311, 385-8 (2006). 3. Gordon, S. P. et al. Pattern formation during de novo assembly of the Arabidopsis shoot meristem. Development 134, 3539-48 (2007). We adapted root tip excision techniques to Arabidopsis, enabling us to perform microarray profiling of regenerating root tissue. Excisions were performed at 4 days post-germination (dpg) at a distance of 130 um from the root tip, resulting in the complete excision of QC, all surrounding stem cells along with several tiers of daughter cells, and the root cap, including all of the columella and most of the lateral root cap. The tip section and then approximately 70 um of regenerating tissue was recut at different time points post cutting. We sampled regenerating stumps at 0hrs, 5 hrs, 13 hrs, 22 hrs, and 7 days after the excision for microarray analysis (Methods). We also sampled root sections immediately above the zone competent to regenerate at 270 um to approximately 340 um. Experiment Overall Design: 30 samples with 4 or 3 replicates for each condition representing a time course of regenerating root stumps and including controls for root tips (regeneration endpoint) at 4 dpg and 8 dpg and a wounded set of samples representing root tissue at 270-340 mm from the root tip for non-regeneration control
Project description:A critical step in regeneration is recreating the cellular identities and patterns of lost organs long after embryogenesis is complete. In plants, perpetual (indeterminate) organ growth occurs in apical stem cell niches, which have been shown to re-establish quickly when damaged or removed (1,2). Here we ask whether the machinery of perpetual organ growth, stem cell activity, is needed for the phase of regeneration that leads to replenishing lost cell identities and patterning, or, whether organ re-establishment enlists a wider group of pluripotent cells. We adapt a root tip regeneration system to Arabidopsis that permits us to assess the molecular and functional recovery of specific cell fates during organ regeneration. These results suggest a rapid restoration of missing cell fate and function in advance of the recovery of stem cell activity. Surprisingly, plants with mutations that fail to maintain stem cell activity were able to re-pattern their distal tip and re-specify lost cell fates. Thus, although stem cell activity is required to resume indeterminate growth (3), our results show it is not necessary for cell re-specification and patterning steps. This implies a regeneration mechanism that coordinates patterning of the whole organ, as in embryogenesis, but is initiated from different starting morphologies. 1. Feldman, L. J. Denovo Origin of Quiescent Center Regenerating Root Apices of Zea-Mays. Planta 128, 207-212 (1976). 2. Xu, J. et al. A molecular framework for plant regeneration. Science 311, 385-8 (2006). 3. Gordon, S. P. et al. Pattern formation during de novo assembly of the Arabidopsis shoot meristem. Development 134, 3539-48 (2007). We adapted root tip excision techniques to Arabidopsis, enabling us to perform microarray profiling of regenerating root tissue. Excisions were performed at 4 days post-germination (dpg) at a distance of 130 um from the root tip, resulting in the complete excision of QC, all surrounding stem cells along with several tiers of daughter cells, and the root cap, including all of the columella and most of the lateral root cap. The tip section and then approximately 70 um of regenerating tissue was recut at different time points post cutting. We sampled regenerating stumps at 0hrs, 5 hrs, 13 hrs, 22 hrs, and 7 days after the excision for microarray analysis (Methods). We also sampled root sections immediately above the zone competent to regenerate at 270 um to approximately 340 um. Keywords: time course, development, root regeneration
Project description:To explore molecular mechanisms of different seed cells in bio-root regeneration, RNA sequencing (RNA-seq) was performed on adipose-derived stromal/stem cells (ASCs) and two dental derived stem cells
Project description:Unlike most animal cells, plant cells can easily regenerate new tissues from a wide variety of organs when properly cultured. The common elements that provide varied plant cells with their remarkable regeneration ability are still largely unknown. Here we describe the initial process of Arabidopsis in vitro regeneration, where a pluripotent cell mass termed callus is induced. We demonstrate that callus resembles the tip of a root meristem, even if it is derived from aerial organs such as petals, which clearly shows that callus formation is not a simple reprogramming process backwards to an undifferentiated state as widely believed. Furthermore, callus formation in roots, cotyledons and petals is blocked in mutant plants incapable of lateral root initiation. It thus appears that the ectopic activation of a lateral root development program is a common mechanism in callus formation from multiple organs. Four sets of biologically independent tissue samples were collect for root, cotyledon and petal explants just after being excised from plants (d0) or after ten days on callus-inducing medium (CIM, d10). Samples derived from the same organ were co-hybridized in the array experiments. Dyes used for labeling the RNA populations derived from the individual samples were switched in the replicate experiments to reduce dye-related artefacts.
Project description:Detached Arabidopsis leaves can regenerate adventitious roots, providing a platform to study de novo root regeneration (DNRR). We performed single-cell RNA-seq analysis and revealed that regeneration primarily originated from vascular stem-cell organizer within procambium, followed by step-by-step changes of transcriptome in cell fate transition, including gradually erasing the vascular stem-cell organizer identity and recruiting the root development program.