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1.
Int J Mol Sci ; 25(9)2024 Apr 23.
Article En | MEDLINE | ID: mdl-38731808

Single-cell RNA sequencing (scRNAseq) is a rapidly advancing field enabling the characterisation of heterogeneous gene expression profiles within a population. The cell cycle phase is a major contributor to gene expression variance between cells and computational analysis tools have been developed to assign cell cycle phases to cells within scRNAseq datasets. Whilst these tools can be extremely useful, all have the drawback that they classify cells as only G1, S or G2/M. Existing discrete cell phase assignment tools are unable to differentiate between G2 and M and continuous-phase-assignment tools are unable to identify a region corresponding specifically to mitosis in a pseudo-timeline for continuous assignment along the cell cycle. In this study, bulk RNA sequencing was used to identify differentially expressed genes between mitotic and interphase cells isolated based on phospho-histone H3 expression using fluorescence-activated cell sorting. These gene lists were used to develop a methodology which can distinguish G2 and M phase cells in scRNAseq datasets. The phase assignment tools present in Seurat were modified to allow for cell cycle phase assignment of all stages of the cell cycle to identify a mitotic-specific cell population.


G2 Phase , Mitosis , Mitosis/genetics , Humans , G2 Phase/genetics , Single-Cell Analysis/methods , Sequence Analysis, RNA/methods , Histones/metabolism , Histones/genetics , Gene Expression Profiling/methods , Computational Biology/methods , Software
2.
Cell Rep ; 43(4): 114073, 2024 Apr 23.
Article En | MEDLINE | ID: mdl-38578825

Macrophages are central innate immune cells whose function declines with age. The molecular mechanisms underlying age-related changes remain poorly understood, particularly in human macrophages. We report a substantial reduction in phagocytosis, migration, and chemotaxis in human monocyte-derived macrophages (MDMs) from older (>50 years old) compared with younger (18-30 years old) donors, alongside downregulation of transcription factors MYC and USF1. In MDMs from young donors, knockdown of MYC or USF1 decreases phagocytosis and chemotaxis and alters the expression of associated genes, alongside adhesion and extracellular matrix remodeling. A concordant dysregulation of MYC and USF1 target genes is also seen in MDMs from older donors. Furthermore, older age and loss of either MYC or USF1 in MDMs leads to an increased cell size, altered morphology, and reduced actin content. Together, these results define MYC and USF1 as key drivers of MDM age-related functional decline and identify downstream targets to improve macrophage function in aging.


Aging , Macrophages , Phagocytosis , Proto-Oncogene Proteins c-myc , Upstream Stimulatory Factors , Humans , Macrophages/metabolism , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Adult , Upstream Stimulatory Factors/metabolism , Upstream Stimulatory Factors/genetics , Middle Aged , Adolescent , Phagocytosis/genetics , Young Adult , Transcription, Genetic , Aged , Chemotaxis/genetics
3.
Nat Commun ; 15(1): 1964, 2024 Mar 11.
Article En | MEDLINE | ID: mdl-38467633

Despite the nuclear localization of the m6A machinery, the genomes of multiple exclusively-cytoplasmic RNA viruses, such as chikungunya (CHIKV) and dengue (DENV), are reported to be extensively m6A-modified. However, these findings are mostly based on m6A-Seq, an antibody-dependent technique with a high rate of false positives. Here, we address the presence of m6A in CHIKV and DENV RNAs. For this, we combine m6A-Seq and the antibody-independent SELECT and nanopore direct RNA sequencing techniques with functional, molecular, and mutagenesis studies. Following this comprehensive analysis, we find no evidence of m6A modification in CHIKV or DENV transcripts. Furthermore, depletion of key components of the host m6A machinery does not affect CHIKV or DENV infection. Moreover, CHIKV or DENV infection has no effect on the m6A machinery's localization. Our results challenge the prevailing notion that m6A modification is a general feature of cytoplasmic RNA viruses and underscore the importance of validating RNA modifications with orthogonal approaches.


Adenosine/analogs & derivatives , Chikungunya Fever , Chikungunya virus , Dengue Virus , Dengue , Humans , Chikungunya virus/genetics , Dengue Virus/genetics , RNA, Viral/genetics , Antibodies, Viral
4.
Blood Adv ; 7(21): 6395-6410, 2023 11 14.
Article En | MEDLINE | ID: mdl-37224458

Deregulated expression of lineage-affiliated transcription factors (TFs) is a major mechanism of oncogenesis. However, how the deregulation of nonlineage affiliated TF affects chromatin to initiate oncogenic transcriptional programs is not well-known. To address this, we studied the chromatin effects imposed by oncogenic MAF as the cancer-initiating driver in the plasma cell cancer multiple myeloma. We found that the ectopically expressed MAF endows myeloma plasma cells with migratory and proliferative transcriptional potential. This potential is regulated by the activation of enhancers and superenhancers, previously inactive in healthy B cells and plasma cells, and the cooperation of MAF with the plasma cell-defining TF IRF4. Forced ectopic MAF expression confirms the de novo ability of oncogenic MAF to convert transcriptionally inert chromatin to active chromatin with the features of superenhancers, leading to the activation of the MAF-specific oncogenic transcriptome and the acquisition of cancer-related cellular phenotypes such as CCR1-dependent cell migration. These findings establish oncogenic MAF as a pioneer transcription factor that can initiate as well as sustain oncogenic transcriptomes and cancer phenotypes. However, despite its pioneer function, myeloma cells remain MAF-dependent, thus validating oncogenic MAF as a therapeutic target that would be able to circumvent the challenges of subsequent genetic diversification driving disease relapse and drug resistance.


Multiple Myeloma , Humans , Multiple Myeloma/drug therapy , Gene Expression Regulation , Plasma Cells/metabolism , B-Lymphocytes/metabolism , Chromatin
5.
Nature ; 609(7929): 1038-1047, 2022 09.
Article En | MEDLINE | ID: mdl-36171374

Oxidative genome damage is an unavoidable consequence of cellular metabolism. It arises at gene regulatory elements by epigenetic demethylation during transcriptional activation1,2. Here we show that promoters are protected from oxidative damage via a process mediated by the nuclear mitotic apparatus protein NuMA (also known as NUMA1). NuMA exhibits genomic occupancy approximately 100 bp around transcription start sites. It binds the initiating form of RNA polymerase II, pause-release factors and single-strand break repair (SSBR) components such as TDP1. The binding is increased on chromatin following oxidative damage, and TDP1 enrichment at damaged chromatin is facilitated by NuMA. Depletion of NuMA increases oxidative damage at promoters. NuMA promotes transcription by limiting the polyADP-ribosylation of RNA polymerase II, increasing its availability and release from pausing at promoters. Metabolic labelling of nascent RNA identifies genes that depend on NuMA for transcription including immediate-early response genes. Complementation of NuMA-deficient cells with a mutant that mediates binding to SSBR, or a mitotic separation-of-function mutant, restores SSBR defects. These findings underscore the importance of oxidative DNA damage repair at gene regulatory elements and describe a process that fulfils this function.


Cell Cycle Proteins , DNA Damage , DNA Repair , Oxidative Stress , Promoter Regions, Genetic , Cell Cycle Proteins/metabolism , Chromatin/genetics , Genes , Genetic Complementation Test , Mitosis , Mutation , Oxidative Stress/genetics , Phosphoric Diester Hydrolases/metabolism , Poly ADP Ribosylation , Promoter Regions, Genetic/genetics , RNA/biosynthesis , RNA/genetics , RNA Polymerase II/metabolism , Spindle Apparatus/metabolism , Transcription Initiation Site
6.
Nat Commun ; 12(1): 5450, 2021 09 14.
Article En | MEDLINE | ID: mdl-34521827

Multiple myeloma is a genetically heterogeneous cancer of the bone marrow plasma cells (PC). Distinct myeloma transcriptome profiles are primarily driven by myeloma initiating events (MIE) and converge into a mutually exclusive overexpression of the CCND1 and CCND2 oncogenes. Here, with reference to their normal counterparts, we find that myeloma PC enhanced chromatin accessibility combined with paired transcriptome profiling can classify MIE-defined genetic subgroups. Across and within different MM genetic subgroups, we ascribe regulation of genes and pathways critical for myeloma biology to unique or shared, developmentally activated or de novo formed candidate enhancers. Such enhancers co-opt recruitment of existing transcription factors, which although not transcriptionally deregulated per se, organise aberrant gene regulatory networks that help identify myeloma cell dependencies with prognostic impact. Finally, we identify and validate the critical super-enhancer that regulates ectopic expression of CCND2 in a subset of patients with MM and in chronic lymphocytic leukemia.


Carcinogenesis/genetics , Cyclin D1/genetics , Cyclin D2/genetics , Gene Expression Regulation, Neoplastic , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Multiple Myeloma/genetics , Transcriptome , Bone Marrow Cells/metabolism , Bone Marrow Cells/pathology , Carcinogenesis/metabolism , Carcinogenesis/pathology , Case-Control Studies , Cell Line, Tumor , Chromatin/chemistry , Chromatin/metabolism , Cyclin D1/metabolism , Cyclin D2/metabolism , Enhancer Elements, Genetic , Gene Expression Profiling , Gene Regulatory Networks , Histone-Lysine N-Methyltransferase/genetics , Histone-Lysine N-Methyltransferase/metabolism , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Multiple Myeloma/metabolism , Multiple Myeloma/mortality , Multiple Myeloma/pathology , Plasma Cells/metabolism , Plasma Cells/pathology , Proto-Oncogene Proteins c-maf/genetics , Proto-Oncogene Proteins c-maf/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , Survival Analysis
7.
Front Immunol ; 11: 574046, 2020.
Article En | MEDLINE | ID: mdl-33329538

The pseudokinase TRIB1 controls cell function in a range of contexts, by regulating MAP kinase activation and mediating protein degradation via the COP1 ubiquitin ligase. TRIB1 regulates polarization of macrophages and dysregulated Trib1 expression in murine models has been shown to alter atherosclerosis burden and adipose homeostasis. Recently, TRIB1 has also been implicated in the pathogenesis of prostate cancer, where it is often overexpressed, even in the absence of genetic amplification. Well described TRIB1 effectors include MAP kinases and C/EBP transcription factors, both in immune cells and in carcinogenesis. However, the mechanisms that regulate TRIB1 itself remain elusive. Here, we show that the long and conserved 3'untranslated region (3'UTR) of TRIB1 is targeted by miRNAs in macrophage and prostate cancer models. By using a systematic in silico analysis, we identified multiple "high confidence" miRNAs potentially binding to the 3'UTR of TRIB1 and report that miR-101-3p and miR-132-3p are direct regulators of TRIB1 expression and function. Binding of miR-101-3p and miR-132-3p to the 3'UTR of TRIB1 mRNA leads to an increased transcription and secretion of interleukin-8. Our data demonstrate that modulation of TRIB1 by miRNAs alters the inflammatory profile of both human macrophages and prostate cancer cells.


Cytokines/metabolism , Intracellular Signaling Peptides and Proteins/physiology , Macrophages/metabolism , MicroRNAs/metabolism , Prostatic Neoplasms/metabolism , Protein Serine-Threonine Kinases/antagonists & inhibitors , 3' Untranslated Regions , Animals , Binding Sites , Cell Line, Tumor , Gene Expression Regulation , Humans , Inflammation , Interleukin-8/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Male , Mice , Mice, Transgenic , MicroRNAs/genetics , Phenotype , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/physiology , RNA, Messenger/genetics , RNA, Messenger/metabolism
8.
Atherosclerosis ; 305: 10-18, 2020 07.
Article En | MEDLINE | ID: mdl-32592946

BACKGROUND AND AIMS: Lipid-rich foam cell macrophages drive atherosclerosis via several mechanisms, including inflammation, lipid uptake, lipid deposition and plaque vulnerability. The atheroma environment shapes macrophage function and phenotype; anti-inflammatory macrophages improve plaque stability while pro-inflammatory macrophages promote rupture. Current evidence suggests a variety of macrophage phenotypes occur in atherosclerotic plaques with local lipids, cytokines, oxidised phospholipids and pathogenic stimuli altering their phenotype. In this study, we addressed differential functioning of macrophage phenotypes via a systematic analysis of in vitro polarised, human monocyte-derived macrophage phenotypes, focussing on molecular events that regulate foam-cell formation. METHODS: We examined transcriptomes, protein levels and functionally determined lipid handling and foam cell formation capacity in macrophages polarised with IFNγ+LPS, IL-4, IL-10, oxPAPC and CXCL4. RESULTS: RNA sequencing of differentially polarised macrophages revealed distinct gene expression changes, with enrichment in atherosclerosis and lipid-associated pathways. Analysis of lipid processing activity showed IL-4 and IL-10 macrophages have higher lipid uptake and foam cell formation activities, while inflammatory and oxPAPC macrophages displayed lower foam cell formation. Inflammatory macrophages showed low lipid uptake, while higher lipid uptake in oxPAPC macrophages was matched by increased lipid efflux capacity. CONCLUSIONS: Atherosclerosis-associated macrophage polarisation dramatically affects lipid handling capacity underpinned by major transcriptomic changes and altered protein levels in lipid-handling gene expression. This leads to phenotype-specific differences in LDL uptake, cellular cholesterol levels and cholesterol efflux, informing how the plaque environment influences atherosclerosis progression by influencing macrophage phenotypes.


Atherosclerosis , Cell Polarity , Lipid Metabolism , Macrophages/cytology , Plaque, Atherosclerotic , Atherosclerosis/genetics , Foam Cells/cytology , Humans , Lipoproteins, LDL , Macrophage Activation
9.
Mol Cell ; 75(2): 310-323.e8, 2019 07 25.
Article En | MEDLINE | ID: mdl-31104896

During gene expression, RNA export factors are mainly known for driving nucleo-cytoplasmic transport. While early studies suggested that the exon junction complex (EJC) provides a binding platform for them, subsequent work proposed that they are only recruited by the cap binding complex to the 5' end of RNAs, as part of TREX. Using iCLIP, we show that the export receptor Nxf1 and two TREX subunits, Alyref and Chtop, are recruited to the whole mRNA co-transcriptionally via splicing but before 3' end processing. Consequently, Alyref alters splicing decisions and Chtop regulates alternative polyadenylation. Alyref is recruited to the 5' end of RNAs by CBC, and our data reveal subsequent binding to RNAs near EJCs. We demonstrate that eIF4A3 stimulates Alyref deposition not only on spliced RNAs close to EJC sites but also on single-exon transcripts. Our study reveals mechanistic insights into the co-transcriptional recruitment of mRNA export factors and how this shapes the human transcriptome.


DEAD-box RNA Helicases/genetics , Eukaryotic Initiation Factor-4A/genetics , Nuclear Proteins/genetics , Nucleocytoplasmic Transport Proteins/genetics , RNA-Binding Proteins/genetics , Transcription Factors/genetics , Transcription, Genetic , Active Transport, Cell Nucleus/genetics , Binding Sites , DEAD-box RNA Helicases/chemistry , Eukaryotic Initiation Factor-4A/chemistry , Exons/genetics , Gene Expression Regulation/genetics , Humans , Nuclear Proteins/chemistry , Nucleocytoplasmic Transport Proteins/chemistry , Polyadenylation , RNA Transport/genetics , RNA, Messenger/chemistry , RNA, Messenger/genetics , RNA-Binding Proteins/chemistry , Transcription Factors/chemistry , Transcriptome/genetics
10.
Sci Rep ; 9(1): 6258, 2019 04 18.
Article En | MEDLINE | ID: mdl-31000734

The chromosome complement of the human fungal pathogen Candida albicans is unusually unstable, suggesting that the process of nuclear division is error prone. The Cdc14 phosphatase plays a key role in organising the intricate choreography of mitosis and cell division. In order to understand the role of Cdc14 in C. albicans we used quantitative proteomics to identify proteins that physically interact with Cdc14. To distinguish genuine Cdc14-interactors from proteins that bound non-specifically to the affinity matrix, we used a substrate trapping mutant combined with mass spectrometry analysis using Stable Isotope Labelling with Amino Acids in Cell Culture (SILAC). The results identified 126 proteins that interact with Cdc14 of which 80% have not previously been identified as Cdc14 interactors in C. albicans or S. cerevisiae. In this set, 55 proteins are known from previous research in S. cerevisiae and S. pombe to play roles in the cell cycle, regulating the attachment of the mitotic spindle to kinetochores, mitotic exit, cytokinesis, licensing of DNA replication by re-activating pre-replication complexes, and DNA repair. Five Cdc14-interacting proteins with previously unknown functions localised to the Spindle Pole Bodies (SPBs). Thus, we have greatly increased the number of proteins that physically interact with Cdc14 in C. albicans.


Candida albicans/cytology , Fungal Proteins/metabolism , Phosphoprotein Phosphatases/metabolism , CDC2 Protein Kinase/metabolism , Candida albicans/metabolism , Cell Cycle , Cell Cycle Proteins/metabolism , Fungal Proteins/genetics , Isotope Labeling , Mass Spectrometry , Mutation , Phosphoprotein Phosphatases/genetics , Protein Interaction Maps/physiology , Protein Tyrosine Phosphatases/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Schizosaccharomyces pombe Proteins/metabolism
11.
Genome Biol ; 20(1): 65, 2019 03 27.
Article En | MEDLINE | ID: mdl-30917859

We introduce alevin, a fast end-to-end pipeline to process droplet-based single-cell RNA sequencing data, performing cell barcode detection, read mapping, unique molecular identifier (UMI) deduplication, gene count estimation, and cell barcode whitelisting. Alevin's approach to UMI deduplication considers transcript-level constraints on the molecules from which UMIs may have arisen and accounts for both gene-unique reads and reads that multimap between genes. This addresses the inherent bias in existing tools which discard gene-ambiguous reads and improves the accuracy of gene abundance estimates. Alevin is considerably faster, typically eight times, than existing gene quantification approaches, while also using less memory.


Sequence Analysis, RNA , Single-Cell Analysis , Software , Animals , DNA Barcoding, Taxonomic , Humans , Mice
12.
Sci Rep ; 8(1): 13827, 2018 09 14.
Article En | MEDLINE | ID: mdl-30218090

N6-methyladenosine (m6A) is the most abundant internal modification of eukaryotic mRNA. This modification has previously been shown to alter the export kinetics for mRNAs though the molecular details surrounding this phenomenon remain poorly understood. Recruitment of the TREX mRNA export complex to mRNA is driven by transcription, 5' capping and pre-mRNA splicing. Here we identify a fourth mechanism in human cells driving the association of TREX with mRNA involving the m6A methylase complex. We show that the m6A complex recruits TREX to m6A modified mRNAs and this process is essential for their efficient export. TREX also stimulates recruitment of the m6A reader protein YTHDC1 to the mRNA and the m6A complex influences the interaction of TREX with YTHDC1. Together our studies reveal a key role for TREX in the export of m6A modified mRNAs.


Adenosine/analogs & derivatives , Exodeoxyribonucleases/metabolism , Phosphoproteins/metabolism , RNA Transport/physiology , Active Transport, Cell Nucleus , Adenosine/metabolism , Adenosine/physiology , Cell Nucleus/metabolism , Cytoplasm/metabolism , Exodeoxyribonucleases/physiology , HEK293 Cells , Humans , Nerve Tissue Proteins/metabolism , Nuclear Proteins/metabolism , Nucleocytoplasmic Transport Proteins/metabolism , Phosphoproteins/physiology , RNA Splicing/physiology , RNA Splicing Factors/metabolism , RNA, Messenger/metabolism , RNA-Binding Proteins/metabolism
13.
Cell Rep ; 23(11): 3352-3365, 2018 06 12.
Article En | MEDLINE | ID: mdl-29898404

Genomic damage can feature DNA-protein crosslinks whereby their acute accumulation is utilized to treat cancer and progressive accumulation causes neurodegeneration. This is typified by tyrosyl DNA phosphodiesterase 1 (TDP1), which repairs topoisomerase-mediated chromosomal breaks. Although TDP1 levels vary in multiple clinical settings, the mechanism underpinning this variation is unknown. We reveal that TDP1 is controlled by ubiquitylation and identify UCHL3 as the deubiquitylase that controls TDP1 proteostasis. Depletion of UCHL3 increases TDP1 ubiquitylation and turnover rate and sensitizes cells to TOP1 poisons. Overexpression of UCHL3, but not a catalytically inactive mutant, suppresses TDP1 ubiquitylation and turnover rate. TDP1 overexpression in the topoisomerase therapy-resistant rhabdomyosarcoma is driven by UCHL3 overexpression. In contrast, UCHL3 is downregulated in spinocerebellar ataxia with axonal neuropathy (SCAN1), causing elevated levels of TDP1 ubiquitylation and faster turnover rate. These data establish UCHL3 as a regulator of TDP1 proteostasis and, consequently, a fine-tuner of protein-linked DNA break repair.


Cysteine Endopeptidases/metabolism , DNA Repair , DNA Topoisomerases, Type I/metabolism , Phosphoric Diester Hydrolases/metabolism , Cell Line, Tumor , Chromosome Breakage , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Down-Regulation , HEK293 Cells , Humans , Nucleotidases/metabolism , Phosphoric Diester Hydrolases/genetics , Proteostasis , RNA Interference , RNA, Small Interfering/metabolism , Ubiquitin/metabolism , Ubiquitin Thiolesterase , Ubiquitination , Up-Regulation
14.
Genome Res ; 27(3): 491-499, 2017 03.
Article En | MEDLINE | ID: mdl-28100584

Unique Molecular Identifiers (UMIs) are random oligonucleotide barcodes that are increasingly used in high-throughput sequencing experiments. Through a UMI, identical copies arising from distinct molecules can be distinguished from those arising through PCR amplification of the same molecule. However, bioinformatic methods to leverage the information from UMIs have yet to be formalized. In particular, sequencing errors in the UMI sequence are often ignored or else resolved in an ad hoc manner. We show that errors in the UMI sequence are common and introduce network-based methods to account for these errors when identifying PCR duplicates. Using these methods, we demonstrate improved quantification accuracy both under simulated conditions and real iCLIP and single-cell RNA-seq data sets. Reproducibility between iCLIP replicates and single-cell RNA-seq clustering are both improved using our proposed network-based method, demonstrating the value of properly accounting for errors in UMIs. These methods are implemented in the open source UMI-tools software package.


Sequence Analysis, DNA/standards , Software , Humans , Sequence Analysis, DNA/methods
15.
PLoS Pathog ; 11(1): e1004630, 2015 Jan.
Article En | MEDLINE | ID: mdl-25617770

The opportunistic human fungal pathogen, Candida albicans, undergoes morphological and transcriptional adaptation in the switch from commensalism to pathogenicity. Although previous gene-knockout studies have identified many factors involved in this transformation, it remains unclear how these factors are regulated to coordinate the switch. Investigating morphogenetic control by post-translational phosphorylation has generated important regulatory insights into this process, especially focusing on coordinated control by the cyclin-dependent kinase Cdc28. Here we have identified the Fkh2 transcription factor as a regulatory target of both Cdc28 and the cell wall biosynthesis kinase Cbk1, in a role distinct from its conserved function in cell cycle progression. In stationary phase yeast cells 2D gel electrophoresis shows that there is a diverse pool of Fkh2 phospho-isoforms. For a short window on hyphal induction, far before START in the cell cycle, the phosphorylation profile is transformed before reverting to the yeast profile. This transformation does not occur when stationary phase cells are reinoculated into fresh medium supporting yeast growth. Mass spectrometry and mutational analyses identified residues phosphorylated by Cdc28 and Cbk1. Substitution of these residues with non-phosphorylatable alanine altered the yeast phosphorylation profile and abrogated the characteristic transformation to the hyphal profile. Transcript profiling of the phosphorylation site mutant revealed that the hyphal phosphorylation profile is required for the expression of genes involved in pathogenesis, host interaction and biofilm formation. We confirmed that these changes in gene expression resulted in corresponding defects in pathogenic processes. Furthermore, we identified that Fkh2 interacts with the chromatin modifier Pob3 in a phosphorylation-dependent manner, thereby providing a possible mechanism by which the phosphorylation of Fkh2 regulates its specificity. Thus, we have discovered a novel cell cycle-independent phospho-regulatory event that subverts a key component of the cell cycle machinery to a role in the switch from commensalism to pathogenicity.


Candida albicans/growth & development , Candida albicans/pathogenicity , Cell Cycle/physiology , Cyclin-Dependent Kinases/metabolism , Forkhead Transcription Factors/metabolism , Candida albicans/genetics , Candida albicans/metabolism , Cell Cycle/genetics , Cell Cycle Proteins/metabolism , Fungal Proteins/metabolism , Gene Expression Profiling , Gene Expression Regulation, Fungal , Host-Pathogen Interactions , Hyphae/genetics , Hyphae/growth & development , Microarray Analysis , Phosphorylation , Protein Processing, Post-Translational
16.
BMC Cancer ; 14: 977, 2014 Dec 18.
Article En | MEDLINE | ID: mdl-25519703

BACKGROUND: Although chemotherapy for prostate cancer (PCa) can improve patient survival, some tumours are chemo-resistant. Tumour molecular profiles may help identify the mechanisms of drug action and identify potential prognostic biomarkers. We performed in vivo transcriptome profiling of pre- and post-treatment prostatic biopsies from patients with advanced hormone-naive prostate cancer treated with docetaxel chemotherapy and androgen deprivation therapy (ADT) with an aim to identify the mechanisms of drug action and identify prognostic biomarkers. METHODS: RNA sequencing (RNA-Seq) was performed on biopsies from four patients before and ~22 weeks after docetaxel and ADT initiation. Gene fusion products and differentially-regulated genes between treatment pairs were identified using TopHat and pathway enrichment analyses undertaken. Publically available datasets were interrogated to perform survival analyses on the gene signatures identified using cBioportal. RESULTS: A number of genomic rearrangements were identified including the TMPRSS2/ERG fusion and 3 novel gene fusions involving the ETS family of transcription factors in patients, both pre and post chemotherapy. In total, gene expression analyses showed differential expression of at least 2 fold in 575 genes in post-chemotherapy biopsies. Of these, pathway analyses identified a panel of 7 genes (ADAM7, FAM72B, BUB1B, CCNB1, CCNB2, TTK, CDK1), including a cell cycle-related geneset, that were differentially-regulated following treatment with docetaxel and ADT. Using cBioportal to interrogate the MSKCC-Prostate Oncogenome Project dataset we observed a statistically-significant reduction in disease-free survival of patients with tumours exhibiting alterations in gene expression of the above panel of 7 genes (p = 0.015). CONCLUSIONS: Here we report on the first "real-time" in vivo RNA-Seq-based transcriptome analysis of clinical PCa from pre- and post-treatment TRUSS-guided biopsies of patients treated with docetaxel chemotherapy plus ADT. We identify a chemotherapy-driven PCa transcriptome profile which includes the down-regulation of important positive regulators of cell cycle progression. A 7 gene signature biomarker panel has also been identified in high-risk prostate cancer patients to be of prognostic value. Future prospective study is warranted to evaluate the clinical value of this panel.


Gene Expression Profiling , Prostatic Neoplasms/genetics , Prostatic Neoplasms/mortality , Transcriptome , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biopsy , Computational Biology , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Humans , Male , Neoplasm Grading , Neoplasm Staging , Prognosis , Prostatic Neoplasms/pathology , Prostatic Neoplasms/therapy
17.
mBio ; 5(1): e00915-13, 2014 Feb 04.
Article En | MEDLINE | ID: mdl-24496790

UNLABELLED: Nap1 has long been identified as a potential septin regulator in yeasts. However, its function and regulation remain poorly defined. Here, we report functional characterization of Nap1 in the human-pathogenic fungus Candida albicans. We find that deletion of NAP1 causes constitutive filamentous growth and changes of septin dynamics. We present evidence that Nap1's cellular localization and function are regulated by phosphorylation. Phos-tag gel electrophoresis revealed that Nap1 phosphorylation is cell cycle dependent, exhibiting the lowest level around the time of bud emergence. Mass spectrometry identified 10 phosphoserine and phosphothreonine residues in a cluster near the N terminus, and mutation of these residues affected Nap1's localization to the septin ring and cellular function. Nap1 phosphorylation involves two septin ring-associated kinases, Cla4 and Gin4, and its dephosphorylation occurs at the septin ring in a manner dependent on the phosphatases PP2A and Cdc14. Furthermore, the nap1Δ/Δ mutant and alleles carrying mutations of the phosphorylation sites exhibited greatly reduced virulence in a mouse model of systemic candidiasis. Together, our findings not only provide new mechanistic insights into Nap1's function and regulation but also suggest the potential to target Nap1 in future therapeutic design. IMPORTANCE: Septins are conserved filament-forming GTPases involved in a wide range of cellular events, such as cytokinesis, exocytosis, and morphogenesis. In Candida albicans, the most prevalent human fungal pathogen, septin functions are indispensable for its virulence. However, the molecular mechanisms by which septin structures are regulated are poorly understood. In this study, we deleted NAP1, a gene encoding a putative septin regulator, in C. albicans and found that cells lacking NAP1 showed abnormalities in morphology, invasive growth, and septin ring dynamics. We identified a conserved N-terminal phosphorylation cluster on Nap1 and demonstrated that phosphorylation at these sites regulates Nap1 localization and function. Importantly, deletion of NAP1 or mutation in the N-terminal phosphorylation cluster strongly reduced the virulence of C. albicans in a mouse model of systemic infection. Thus, this study not only provides mechanistic insights into septin regulation but also suggests Nap1 as a potential antifungal target.


Candida albicans/genetics , Candida albicans/metabolism , Gene Expression Regulation, Fungal , Macromolecular Substances/metabolism , Nucleosome Assembly Protein 1/metabolism , Septins/metabolism , Animals , Candida albicans/cytology , Candida albicans/growth & development , Candidiasis/microbiology , Candidiasis/pathology , Cell Cycle , Disease Models, Animal , Fungal Proteins/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Deletion , Mass Spectrometry , Mice , Mice, Inbred BALB C , Mutagenesis, Site-Directed , Nucleosome Assembly Protein 1/chemistry , Nucleosome Assembly Protein 1/genetics , Phosphorylation , Protein Processing, Post-Translational , Virulence
18.
Bioinformatics ; 30(9): 1290-1, 2014 May 01.
Article En | MEDLINE | ID: mdl-24395753

Computational genomics seeks to draw biological inferences from genomic datasets, often by integrating and contextualizing next-generation sequencing data. CGAT provides an extensive suite of tools designed to assist in the analysis of genome scale data from a range of standard file formats. The toolkit enables filtering, comparison, conversion, summarization and annotation of genomic intervals, gene sets and sequences. The tools can both be run from the Unix command line and installed into visual workflow builders, such as Galaxy.


Genomics/methods , Databases, Genetic , High-Throughput Nucleotide Sequencing , Software , Workflow
19.
Nat Rev Genet ; 15(2): 121-32, 2014 Feb.
Article En | MEDLINE | ID: mdl-24434847

Sequencing technologies have placed a wide range of genomic analyses within the capabilities of many laboratories. However, sequencing costs often set limits to the amount of sequences that can be generated and, consequently, the biological outcomes that can be achieved from an experimental design. In this Review, we discuss the issue of sequencing depth in the design of next-generation sequencing experiments. We review current guidelines and precedents on the issue of coverage, as well as their underlying considerations, for four major study designs, which include de novo genome sequencing, genome resequencing, transcriptome sequencing and genomic location analyses (for example, chromatin immunoprecipitation followed by sequencing (ChIP-seq) and chromosome conformation capture (3C)).


Chromatin Immunoprecipitation/methods , Gene Expression Profiling/methods , Genomics/methods , High-Throughput Nucleotide Sequencing/methods , Animals , Guidelines as Topic , Humans
20.
Eur Urol ; 66(1): 32-9, 2014 Jul.
Article En | MEDLINE | ID: mdl-24054872

BACKGROUND: Androgen-deprivation therapy (ADT) is standard treatment for locally advanced or metastatic prostate cancer (PCa). Many patients develop castration resistance (castration-resistant PCa [CRPC]) after approximately 2-3 yr, with a poor prognosis. The molecular mechanisms underlying CRPC progression are unclear. OBJECTIVE: To undertake quantitative tumour transcriptome profiling prior to and following ADT to identify functionally important androgen-regulated pathways or genes that may be reactivated in CRPC. DESIGN, SETTING, AND PARTICIPANTS: RNA sequencing (RNA-seq) was performed on tumour-rich, targeted prostatic biopsies from seven patients with locally advanced or metastatic PCa before and approximately 22 wk after ADT initiation. Differentially regulated genes were identified in treatment pairs and further investigated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) on cell lines and immunohistochemistry on a separate CRPC patient cohort. Functional assays were used to determine the effect of pathway modulation on cell phenotypes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We searched for gene expression changes affecting key cell signalling pathways that may be targeted as proof of principle in a CRPC in vitro cell line model. RESULTS AND LIMITATIONS: We identified ADT-regulated signalling pathways, including the Wnt/ß-catenin signalling pathway, and observed overexpression of ß-catenin in a subset of CRPC by immunohistochemistry. We validated 6 of 12 (50%) pathway members by qRT-PCR on LNCaP/LNCaP-AI cell RNAs, of which 4 (67%) demonstrated expression changes consistent with RNA-seq data. We show that the tankyrase inhibitor XAV939 (which promotes ß-catenin degradation) reduced androgen-independent LNCaP-AI cell line growth compared with androgen-responsive LNCaP cells via an accumulation of cell proportions in the G0/G1 phase and reduction in the S and G2/M phases. Our biopsy protocol did not account for tumour heterogeneity, and pathway inhibition was limited to pharmacologic approaches. CONCLUSIONS: RNA-seq of paired PCa samples revealed ADT-regulated signalling pathways. Proof-of-principle inhibition of the Wnt/ß-catenin signalling pathway specifically delays androgen-independent PCa cell cycle progression and proliferation and warrants further investigation as a potential target for therapy for CRPC.


Gene Expression , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/genetics , RNA, Neoplasm/analysis , Wnt Signaling Pathway/genetics , beta Catenin/genetics , Aged , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Enzyme Inhibitors/pharmacology , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Heterocyclic Compounds, 3-Ring/pharmacology , Humans , Male , Middle Aged , Prostatic Neoplasms, Castration-Resistant/chemistry , Sequence Analysis, RNA/methods , Transcriptome , beta Catenin/analysis
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