Time course infection of HeLa cells by Chlamydia tracomatis
Ontology highlight
ABSTRACT: Human Hela cells were infected with Chtrac L2 at timepoints t2hrs, t4hrs, t10hrs, t24hrs and t43hrs including controls without infection at t0 and t24hrs.
Project description:The obligate intracellular developmental cycle of Chlamydia trachomatis presents significant challenges in defining its proteome. In this study we have applied quantitative proteomics to both the intracellular reticulate body (RB) and the extracellular elementary body (EB) from C. trachomatis. We used C. trachomatis L2 which is a model chlamydial isolate for such a study since it has a high infectivity: particle ratio and there is an excellent quality genome sequence. EBs and RBs (>99% pure) were quantified by chromosomal and plasmid copy number using PCR to determine the concentrations of chlamydial proteins per bacterial cell. RBs harvested at 15h post infection (PI) were purified by three successive rounds of gradient centrifugation. This is the earliest possible time to obtain purified RBs, free from host cell components in quantity, within the constraints of the technology, EBs were purified at 48h PI. We then used two-dimensional reverse phase UPLC to fractionate RB or EB peptides before mass spectroscopic analysis, providing absolute amount estimates of chlamydial proteins.
Project description:Lysosomal acid lipase (LAL) is the key enzyme of lysosomal lipid hydrolysis, which degrades cholesteryl esters (CE), triacylglycerols (TG), diacylglycerols (DG), and retinyl esters. The role of LAL in various cellular processes has mostly been studied in LAL-deficient (Lal-/-) mice, which share phenotypical characteristics with humans suffering from LAL deficiency. In vitro, the cell-specific functions of LAL have been commonly investigated by using the LAL inhibitors Lalistat-1 (L1) and Lalistat-2 (L2). Here, we show that pharmacological LAL inhibition but not genetic loss of LAL impairs isoproterenol-stimulated lipolysis and neutral TG hydrolase (TGH) and CE hydrolase (CEH) activities in mature adipocytes, indicating that L1 and L2 inhibit other lipid hydrolases apart from LAL. Since adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) are the major enzymes that degrade cytosolic TG and CE, respectively, at neutral pH, we hypothesized that L1 and L2 also inhibit ATGL and/or HSL through off-target effects. In fact, both inhibitors drastically reduced neutral CEH activity in cells overexpressing mouse and human HSL and neutral TGH activity in cells overexpressing mouse and human ATGL, albeit to a lesser extent. By performing serine hydrolase-specific activity-based labeling in combination with quantitative proteomics, we confirmed that L2 inhibits HSL and other lipid hydrolases, whereas L1 treatment results in less pronounced inhibition of neutral lipid hydrolases. These results demonstrate that commonly used concentrations of L2 (and L1) are not suitable for investigating the role of LAL-specific lipolysis in lysosomal function, signaling pathways, and autophagy.
Project description:Cell cycle progression into mitosis induce cellular rearrangements such as mitotic spindle formation, Golgi fragmentation, and nuclear envelope breakdown. Like certain retroviruses, nuclear delivery of HPV16 genomes is facilitated by these processes during entry into host cells by tethering of the viral DNA to mitotic chromosomes through the minor capsid protein L2. However, the mechanism of delivery onto and tethering to the condensed chromosomes is barely understood on a mechanistic level. To date it is unclear, which cellular proteins facilitate this process in interaction with L2 or how this process is regulated. Here, we discovered that HPV16 minor capsid protein L2 is phosphorylated during entry upon mitosis onset on conserved residues within the chromosome-binding region (CBR) that is responsible for nuclear import. The crucial L2 phosphorylations occurred sequentially by the master mitotic kinases CDK1 and PLK1. L2 phosphorylation, thus, not only regulated timely delivery of HPV16 vDNA to mitotic chromatin at mitosis onset, but also likely resulted in a conformational switch in L2 that allowed engagement of cellular proteins for this purpose. In summary, our work demonstrates for the first time a crucial role of mitotic kinases for nuclear entry of a DNA virus and provides important insights into the molecular mechanism of pathogen import into the nucleus during mitosis.
Project description:All above ground organs of higher plants are ultimately derived from shoot apical meristems (SAMs). The SAM exhibits distinctive structural organization, and monocot SAMs such as maize are comprised of two cell layers, a single cell layered tunica (L1) and a corpus (L2). Although recent research has revealed roles of these cell layers in the SAM, intra- and inter-cell-layer signaling networks involved in organ development remain largely unknown except for a few differentially expressed genes. Here, we used Illumnia technology to conduct RNA-seq of L1 and L2 cell layers in maize B73 maize shoot apical meristem. Single sequencing library was constructed for L1 and L2 cell layer. Each library was sequenced using 2 lanes on a Solexa flow cell. Processed data file 'ZmB73_4a.53_filtered_genes.fasta' and its README file are linked below as supplementary files. The fasta file contains the gene model ID and corresponding sequence generated from maize genome project. This fasta file was used for the following samples: GSM418173, GSM418174, GSM420173, GSM420174, GSM422828, GSM422829.
Project description:By comprehensive quantitative proteome analysis we characterize the three growth forms elementary body (EB), reticulate body (RB) and aberrant reticulate body (ARB) of Chlamydia trachomatis genital strain D/UW-3/CX
Project description:In this project we examined in-vitro effect of female sex hormones, estradiol and progesterone at average physiological concentration level on Chlamydia trachomatis gene expression level. Regulation of chlamydial gene expression by the female sex hormones oestradiol and progesterone was examined. A total of 16 chlamydial arrays were analysed with the 4 culture conditions (no hormone, E, P, E+P) x four replicates. Bacterial samples were grown in non-hormone treated culture were used as control
Project description:C. trachomatis possess a cryptic 7.5 kb plasmid of unknown function. Here we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human Chlamydia trachomatis strain L2 (25667R). We found that despite minimal chromosomal polymorphisms the LGV L2 (25667R) strain was indistinguishable from the L2 (434) plasmid positive strain in its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The primary in vitro phenotypic differences between L2 (434) and L2 (25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intra-inclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their ability to colonize and infect the female mouse genital tract. The ID50 of the L2 (25667R) plasmidless strain was 500 fold greater (1.XX x 10X IFU) than the L2 (434) plasmid bearing strain (1. XX x 10X IFU). Transcriptome analysis of the two strains clearly demonstrated a decrease in transcript levels of a subset of chromosomal genes for the L2 (25667R) strain. Among those genes was glgA which encodes for glycogen synthase; a finding consistent with the failure of the L2 (25667R) strain to accumulate glycogen granules. Collectively, these findings support an important role for the plasmid in in vivo infectivity and suggest that this virulence characteristic might be controlled by the plasmids ability to regulate the expression of specific chromosomal genes. These results also support an important role for the plasmid in the pathogenesis of human infection and disease. Keywords: strain comparison C. trachomatis strain L2-25667R compared to strain L2-434
Project description:C. trachomatis possess a cryptic 7.5 kb plasmid of unknown function. Here we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human Chlamydia trachomatis strain L2 (25667R). We found that despite minimal chromosomal polymorphisms the LGV L2 (25667R) strain was indistinguishable from the L2 (434) plasmid positive strain in its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The primary in vitro phenotypic differences between L2 (434) and L2 (25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intra-inclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their ability to colonize and infect the female mouse genital tract. The ID50 of the L2 (25667R) plasmidless strain was 500 fold greater (1.XX x 10X IFU) than the L2 (434) plasmid bearing strain (1. XX x 10X IFU). Transcriptome analysis of the two strains clearly demonstrated a decrease in transcript levels of a subset of chromosomal genes for the L2 (25667R) strain. Among those genes was glgA which encodes for glycogen synthase; a finding consistent with the failure of the L2 (25667R) strain to accumulate glycogen granules. Collectively, these findings support an important role for the plasmid in in vivo infectivity and suggest that this virulence characteristic might be controlled by the plasmids ability to regulate the expression of specific chromosomal genes. These results also support an important role for the plasmid in the pathogenesis of human infection and disease. Keywords: strain comparison
Project description:The 3' untranslated region (3'UTR) constitutes a major site of post-transcriptional regulation of gene expression. Sequence elements in the 3'UTR interact with trans-acting regulators such as microRNAs that affect translation and stability. The overall aim is to use a 3'RACE cloning-sequencing stragety to identify the 3'UTRs of C. elegans transcripts and explore their heterogeneity in different developmental stages and tissues. Keywords: Transcriptome analysis For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Raw data files are available on our FTP site: ftp://ftp.ncbi.nlm.nih.gov/pub/geosup/Series/GSE17781 pilot study [GSM443959..GSM443964]: N2 wildtype worms staged at embryo, L1, L2, L3, L4, and adult full experiment [GSM446651..GSM446661]: N2 wildtype worms staged at embryo, L1, L2, L3, L4, dauer, and adult. Illumina Genome Analyzer sequencing of isolated clones [GSM469439] 454 sequencing of RACE clones [GSM469976]