Project description:Pre-mRNA splicing requires assembly of spliceosome that consists of hundreds of factors forming various dynamic complexes with or without small nuclear RNAs (snRNAs). Systematic identification of the splicing factors remains a significant challenge especially in vivo. In our genetic screening for the factors required for division asynchrony during Caenorhabditis elegans embryogenesis, we identified a highly conserved but uncharacterized essential protein, GAD-1, that is necessary for setting cell cycle length of intestine progenitors, a function that is shared with many other factors involved in transcription, pre-mRNA splicing or polyadenylation, suggesting its potential role in mRNA biogenesis. Co-immunoprecipitation followed by mass spectrometry reveals that GAD-1 mainly interacts with non-snRNP type of splicing complex called NineTeen Complex (NTC). Consistent with this, RNA-seq analysis demonstrates pervasive defects in pre-mRNA splicing in gad-1 mutants. Transgenic reporter assay shows its ubiquitous and nuclear expression across developmental stages. Immunostaining of the C-terminal domain of RNA polymerase II demonstrates a GAD-1’s role in transcription elongation. In agreement with this, depletion of GAD-1 and its interacting partners inhibits expression of both ubiquitous and tissue-specific genes, supporting that both GAD-1 and many of its interacting proteins are novel components of NTC or its associated spliceosome. Taken together, we identify GAD-1 and its multiple interacting partners as novel components of spliceosome in vivo through which they regulate pre-mRNA splicing and transcription elongation.
Project description:To compare transcriptional profiling of a gadE-, hdeA-, or hdeD- deficient strain to wild type in E. coli under minimum medium conditions. These genes are included in the GAD cluster genes, which are involved in the glutamic acid-dependent acid resistance (GAD) in E. coli. Goal was to determine the GadE, HdeA, or HdeD regulon in E. coli. Biological replicates: 2 replicates.
Project description:Anxiety disorders refer to a group of costly psychiatric disorders characterized by feelings of fear, panic and worry and related behavioral disturbances. Up to 275 million people worldwide (4% of the global population) are affected by anxiety disorders, which was ranked 8th of the top 25 leading causes of years lived with disability (YLDs) in 2019. According to a recent article published in the Lancet, the COVID-19 pandemic has led to a substantial rise in prevalence of GAD globally, consequently contributing to an elevated disease burden and a deteriorated economic situation. However, around 50% of patients diagnosed with generalized anxiety disorder (GAD) do not respond to the conventional pharmacological and psychological interventions due to the individual variability. Moreover, the limited accessibility to mental health professionals, the risk of dependence on benzodiazepines and the side effects of selective serotonin reuptake inhibitors (SSRIs) can negatively influence the medication adherence of patients. Hence, there is an urgent need to investigate the underlying pathological mechanisms and develop innovative therapeutic interventions for GAD.
Project description:Background: Of the many neurotransmitters in humans, gamma-aminobutyric acid (GABA) shows potential for improving several mental health indications such as stress and anxiety. The microbiota-gut-brain axis is an important pathway for GABAergic effects, as microbially-secreted GABA within the gut can affect host mental functionhealth outcomes. Understanding the molecular characteristics of GABA production by microbes within the gut can offer insight to novel therapies for mental health. Results: Three strains of Levilactobacillus brevis with syntenous glutamate decarboxylase (GAD) operons were evaluated for overall growth, glutamate utilization, and GABA production in typical synthetic growth media supplemented with monosodium glutamate (MSG). Levilactobacillus brevis Lbr-6108 (Lbr-6108) and Levilactobacillus brevis Lbr-35 (Lbr-35) had similar growth profiles but differed significantly in GABA secretion and acid resistance. Lbr-6108 produced GABA early, within the growth phase, and produced significantly more GABA than Lbr-35 and the type strain Levilactobacillus brevis ATCC 14689 after the stationary phase. The global gene expression during GABA production was determined by RNA sequencing at several timepoints. The GAD operon, responsible for GABA production and secretion, activated in Lbr-6108 after only six hours of fermentation and continued throughout the stationary phase. Furthermore, Lbr-6108 activated many different acid resistance mechanisms concurrently, which contribute to acid tolerance and energy production. In contrast, Lbr-35, which has a genetically similar GAD operon, including two copies of the GAD gene, showed no upregulation of the GAD operon, even when cultured with MSG. Conclusions: This study is the first to evaluate whole transcriptome changes in L. brevis during GABA production over multiple timepoints. The concurrent expression of multiple acid-resistance mechanisms reveals niche-specific metabolic functionality between common human commensals and highlights the complex regulation of GABA metabolism in this important microbial species. Furthermore, the increased and rapid GABA production of Lbr-6108 highlights the strain’s potential as a therapeutic and the overall value of screening microbes for effector molecule output.
Project description:Background: The soil environment is responsible for sustaining most terrestrial plant life on earth, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere and how it responds to agricultural management such as crop rotations and soil tillage will be vital for improving global food production. Methods: The rhizosphere soils of wheat and chickpea growing under + and - decaying root were collected for metagenomics sequencing. A gene catalogue was established by de novo assembling metagenomic sequencing. Genes abundance was compared between bulk soil and rhizosphere soils under different treatments. Conclusions: The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the microbiome from decaying root in determining the metagenome of developing root systems, which is fundamental to plant growth, since roots preferentially inhabit previous root channels. Modifications in root microbial function through soil management, can ultimately govern plant health, productivity and food security.
Project description:DNA, RNA and protein were extracted from the culture and subjected to massive parallel sequencing and nano-LC-MS-MS respectively Combination of these methods enabled the reconstruction of the complete genome sequence of M oxyfera from the metagenome and identification of the functionally relevant enzymes and genes
Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification