Transcriptome analysis of L-form, protoplast of the B. subtilis cells
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ABSTRACT: To investigate whether the oxidative stress response is induced in protoplasts, we compared the gene expression patterns of protoplasts to those of walled cells and L-forms using microarrays.
Project description:The goal of this experiment was to investigate the early transcript changes (6h) induced by hypoxia treatment in mesophyll protoplasts. A single pair (control & hypoxia) of GeneChips® was used to confirm that hypoxia treatment altered the expression of an overlapping set of genes controlled by KIN10 (At3g01090) in Arabidopsis mesophyll protoplasts. Experiment Overall Design: For the hypoxic treatment protoplasts were submerged in mannitol buffer and the hypoxia condition was confirmed by the activation of the well-established early marker genes ADH (alcohol dehydrogenase, At1g77120) and PDC1 (pyruvate decarboxylase-1, At4g33070) based on RT-PCR and GeneChip® analyses. Results show a clear overlap in genes induced under hypoxic conditions and those induced by KIN10 expression in protoplasts. The overlap of the gene expression profiles was confirmed by triplicated real-time quantitative RT-PCR analyses of selected marker genes.
Project description:The past twenty years have seen tremendous advances in our understanding of the mechanisms underlying bacterial cytokinesis, particularly the composition of the division machinery and the factors controlling its assembly. At the same time, however, we understand very little about the relationship between cell division and other cell cycle events in bacteria. Here we report that inhibiting division in Bacillus subtilis and Staphylococcus aureus quickly leads to an arrest in the initiation of new rounds of DNA replication followed by a complete arrest in cell growth. Arrested cells are metabolically active but unable to initiate new rounds of either DNA replication or division when shifted to permissive conditions. Inhibiting DNA replication results in entry into a similar quiescent state, in which cells are unable to resume growth or division when returned to permissive conditions. Our findings suggest the presence of two cell cycle control points: one linking division to the initiation of DNA replication and another linking the initiation of DNA replication to division. Significantly, this evidence contradicts the prevailing view of the bacterial cell cycle as a series of coordinated but uncoupled events. Importantly, the terminal nature of the cell cycle arrest validates the bacterial cell cycle machinery as an effective target for antimicrobial development. Four-condition experiment: ftsZ induced for 1hr, ftsZ depleted for 1hr, ftsZ induced for 2hrs, ftsZ depleted for 2hrs. Biological replicates: 3-4 for each sample. Reference: a mixture of wt RNA from different growth phases and wt backgrounds.
Project description:Common transcriptional responses of Arabidopsis thaliana protoplasts transfected with turnip crinkle virus (TCV) , hibiscus chlorotic ringspot virus (HCRSV) and their coat protein mutants.
Project description:The goal of this experiment was to explore the extent of KIN10 (At3g01090) transcriptional regulation and identify its early target genes in Arabidopsis mesophyll protoplasts. Results suggest that KIN10 targets a remarkably broad array of genes that orchestrate transcription networks, promote catabolism and autophagy, and suppress anabolism and ribosome biogenesis. The transient expression condition ruled out secondary or long-term effects of metabolism and growth, and circumvented experimental limitations caused by redundancy and embryonic lethality observed in mammals and plants. Experiment Overall Design: Analysis of the transcript changes induced by transient KIN10 (At3g01090) expression (6h) in Arabidopsis mesophyll protoplasts using protoplasts similarly transfected with control plasmid DNA for comparison. To maximize the significance of the duplicated experimental data for defining differentially expressed genes, the biologically independent experiments were carefully performed by two individuals using different soil, plants, growth chambers, DNAs and microarray facilities for hybridization and scanning to cover potential technical and biological variations. For each pair (control & KIN10) of large-scale protoplast transfection experiments, about 3 million protoplasts were isolated from the fifth and sixth leaves of 36 randomly picked plants and pooled. Experiment Overall Design: RNA samples isolated from control and KIN10-transfected protoplasts were subjected to quality controls, including RNA quality and quantity inspection by gel electrophoresis and staining as well as consistent gene expression changes by duplicated real-time quantitative RT-PCR analyses of selected marker genes.
Project description:The goal of this experiment was to identify the early target genes of constitutively activated CPK5ac and CPK11ac in Arabidopsis mesophyll cells that are involved in early flagellin responses important for plant innate immunity. We used the microarrays to detail the global program of gene expression underlying initial calcium responses to microbial associated molecualr patterns (MAMPs). Arabidopsis mesophyll protoplasts were transfected with plasmid DNA to express constitutively active CPK5ac or CPK11ac for 6 hr. Transcript profiles were analyzed and compared between cells transfected with control DNA and CPK5ac or CPK11ac DNA to identify early CPK5ac and CPK11ac target genes.
Project description:This work studies the impact of AtNIGT1/HRS1-GR entrance in the nucleus upond DEX treatment in protoplasts. AtNIGT1/HRS1 TARGET. The whole procedure has been performed as previously described in Bargmann et al Mol Plant 2013. In brief, the protoplasts were transfected with the plasmid pBeaconRFP_GR-HRS1 that trigger the expression of HRS1 protein fused with the glucocorticoid receptor under control of CaMV35S promoter. Protoplasts were treated with 35µM cycloheximide (CHX) to inhibit translation and to select only direct target genes and 10µM dexamethasone (DEX) to induce HRS1-GR entry in the nucleus. Nitrate is maintained during the whole TARGET procedure. The Red Fluorescent Protein was used as marker selection for fluorescent-activated cell sorting (FACS) of successfully transformed protoplasts. RNA were extracted and amplified in order to be tested with ATH1 Affymetrix™ chips.
Project description:Transient genetic modification of plant protoplasts is a straightforward and rapid technique for the analysis of numerous aspects of plant biology. One drawback in the analysis of transformed protoplast suspensions is that they are a heterogeneous mix of cells that have and have not been successfully transfected. To overcome this problem, we have developed a system that employs a fluorescent positive selection marker in combination with flow cytometric analysis as well as fluorescence activated cell sorting (FACS) to isolate responses in the transfected protoplasts exclusively. This recombinase-compatible system enables high-throughput screening of genetic circuitry. Moreover, the use of FACS allows in depth downstream analysis. Lastly, over-expression is an effective means to dissect regulatory networks, especially where redundancy exists. Here, this system has been applied to the study of auxin signaling in order to investigate reporter gene activation and genome-wide transcriptional changes in response to manipulation of the auxin-response network. We have transiently over-expressed dominant negative mutant isoforms of Aux/IAA transcription factors (IAA7mII and IAA19mII; Tiwari et al., 2001) in Arabidopsis Pwer::GFP root protoplasts, making use of a RFP fluorescent positive selection marker and FACS to isolate the dually labeled (IAAnmII expressing and Pwer::GFP-positive) cells. We have compared the transcriptional differences between an empty vector control, IAA7mII and IAA19mII protoplasts that had either been treated with 5microM IAA or mock-treated for 3 hours. Experiment Overall Design: 18 samples with 3 replicates for each condition and transformation vector: 3x empty vector mock treated, 3x empty vector IAA treated, 3x IAA7mII over-expressor mock treated, 3x IAA7mII over-expressor IAA treated, 3x IAA19mII over-expressor mock treated and 3x IAA19mII over-expressor IAA treated.
Project description:Virus infection induces activation and suppression of global gene expression in the host. Profiling gene expression changes in the host may provide insights into the molecular mechanisms that underlie host physiological and phenotypic responses to virus infection. In this study, the Arabidopsis Affymetrix ATH1 whole genome array was used to assess global gene expression changes in Arabidopsis thaliana plants infected with Plum pox virus (PPV). To identify early genes in response to PPV infection, an Arabidopsis synchronized single-cell transformation system was developed. Arabidopsis protoplasts were transfected with a PPV infectious clone, PPV-SK68 and global gene expression changes in the transfected protoplasts were profiled. Experiment Overall Design: For PPV infection in Arabdiopsis leaves, eight independent hybridizations were performed using total RNA isolated from three independent biological replicates of the virus-infected or mock-inoculated control samples. Experiment Overall Design: For PPV infection in Arabidopsis protoplasts, 24 gene chips in total were used to hybridize with RNA isolated from protoplasts transfected with PPV infectious clone and PPV deletion mutant.
Project description:The goal of this experiment was to identify the early responsive genes activated by the 22 amino acid peptide of bacterial flagellin (flg22) in Arabidopsis mesophyll cells that are involved in the initial responses important for plant innate immunity. We used the microarrays to detail the global program of gene expression underlying intial cellular and molecular responses to microbial associated molecualr patterns (MAMPs). Arabidopsis mesophyll protoplasts were treated with 100 nM flg22 for 30 min and 60 min. Transcript profiles were analyzed and compared between control and treated cells to identify early flg22 responsive genes.
Project description:Deciphering gene regulatory networks (GRNs) is a key for understanding gene expression regulations in living systems. Here, we describe the investigation of the ABSCISIC ACID INSENSITIVE 3 (ABI3) plant transcription factor GRN vicinity by a technique called Network Walking. The method involves transient transformation of protoplasts and inducible nuclear re-localization of transcription factors along with transcriptomic analysis. This genome-wide approach allowed the de novo recovery of i) direct and indirect ABI3 target genes, ii) cis-binding site preference, and iii) biological processes regulated by this canonical abscisic acid response factor. This work improves our knowledge of ABI3 action by inferring network motifs (such as Feed Forwar Loops) under its influence. The novel high-throughput-oriented technique will help accelerate GRN systems investigations in plants, as well as in other organisms. This work studies ABI3 direct and indirect targets by a technique named Network Walking. Root/protoplasts were treated with or without dexamethasone (DEX) and cycloheximide (CHX). 3 reps each.