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1.
Int J Tuberc Lung Dis ; 25(6): 491-497, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34049612

RESUMO

BACKGROUND: In March 2011, the Department of Public Health East in Ireland were notified of two cases of TB in two prisoners sharing a cell. We define the resulting outbreak and highlight the role of public health and laboratory-based molecular epidemiology in mapping and control of a prison outbreak.METHODS: Cases were identified through clinical presentation, contact tracing, case-finding exercise or enhanced laboratory surveillance. Mycobacterium tuberculosis isolates were genotyped and underwent whole-genome sequencing (WGS).RESULTS: Of the 34 cases of TB linked to the outbreak, 27 were prisoners (79%), 4 prison officers (12%) and 3 community cases (9%). M. tuberculosis was isolated from 31 cases (culture positivity: 91%). A maximum of six single-nucleotide polymorphisms separated the isolates, with 22 being identical, suggestive of a highly infectious 'super-spreader´ within the prison. Isolates belonged to the Beijing sub-lineage, and were susceptible to first-line anti-TB agents. A case-finding exercise incidentally detected a prisoner with multidrug-resistant TB. Of the 143 prison officers screened, 52% had latent TB infection. Litigation costs exceeded five million euros.CONCLUSION: This constitutes the largest prison outbreak of TB in Western Europe investigated using WGS. A robust prison entry TB screening and education programme is required to effect better TB control, and prevent future outbreaks and attendant litigation.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Surtos de Doenças , Europa (Continente) , Humanos , Mycobacterium tuberculosis/genética , Prisões , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
2.
J Emerg Manag ; 17(3): 199-209, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31245830

RESUMO

INTRODUCTION: From 2009 to 2016, the Centers for Disease Control and Prevention (CDC) activated its Incident Management System for a public health emergency 91 percent of the time. The CDC must ensure its workforce is prepared for the evolving nature of emergencies. OBJECTIVES: The purpose of this assessment was to identify perceived preparedness and response training needs for the CDC responder workforce. METHODS: Between November 2012 and January 2013, focus groups and in-depth interviews were conducted with CDC responders, including senior leaders. The evaluation questions were: (1) How well does the current training system prepare CDC staff to respond to emergency events? (2) What gaps exist in the current training system? and (3) What trainings are essential and should be included in the training system? RESULTS: Eight focus groups were conducted with 51 responders and 18 interviews with response leaders. Themes were identified for each main outcome measure and translated to training improvements. CONCLUSIONS: The CDC workforce received foundational training. Recommendations are provided to better prepare responders during an emergency. Periodic assessments are necessary to expand training and remain responsive to the complexities of emerging threats.


Assuntos
Emergências , Saúde Pública , Recursos Humanos , Centers for Disease Control and Prevention, U.S. , Humanos , Estados Unidos
3.
Epidemiol Infect ; 146(6): 705-711, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29582721

RESUMO

Hepatitis A infection results in a spectrum of illness from asymptomatic disease to severe fulminant hepatitis. Since 2000, <50 cases have been reported annually in Ireland. We report on an outbreak of hepatitis A associated with a childcare facility(CCF) in 2015 in Ireland. Between January and July 2015, 12 outbreak-associated symptomatic hepatitis A cases were identified, including one delayed, retrospective diagnosis. Seven (58%) cases were adults, eight (67%) were male, six of the adults required hospitalisation. All 12 cases were confirmed on serology and the four cases that were genotyped were identical on phylogenetic analysis. Potential environmental exposures and hygiene practices at the CCF were investigated. Outbreak control measures included the provision of: hepatitis A information, infection prevention advice, hepatitis A vaccination to 554 CCF contacts, and voluntary closure of the CCF for deep-cleaning and staff education. From a healthcare perspective1, outbreak control costs were in excess of €45 000. This outbreak illustrates the considerable adult morbidity that can occur in hepatitis A outbreaks, highlights the challenges in controlling a large CCF-associated outbreak and the importance of early recognition by clinicians of hepatitis A.


Assuntos
Surtos de Doenças , Hepatite A/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Genótipo , Vírus da Hepatite A/classificação , Vírus da Hepatite A/genética , Humanos , Lactente , Irlanda/epidemiologia , Masculino , Pessoa de Meia-Idade , Filogenia , Estudos Retrospectivos , Testes Sorológicos
4.
J Infect ; 76(1): 55-67, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29031637

RESUMO

OBJECTIVES: The primary objective of this work was to examine the acquisition and spread of multi-drug resistant (MDR) tuberculosis (TB) in Ireland. METHODS: All available Mycobacterium tuberculosis complex (MTBC) isolates (n = 42), from MDR-TB cases diagnosed in Ireland between 2001 and 2014, were analysed using phenotypic drug-susceptibility testing, Mycobacterial-Interspersed-Repetitive-Units Variable-Number Tandem-Repeat (MIRU-VNTR) genotyping, and whole-genome sequencing (WGS). RESULTS: The lineage distribution of the MDR-TB isolates comprised 54.7% Euro-American, 33.3% East Asian, 7.2% East African Indian, and 4.8% Indo-Oceanic. A significant association was identified between the East Asian Beijing sub-lineage and the relative risk of an isolate being MDR. Over 75% of MDR-TB cases were confirmed in non-Irish born individuals and 7 MIRU-VNTR genotypes were identical to clusters in other European countries indicating cross-border spread of MDR-TB to Ireland. WGS data provided the first evidence in Ireland of in vivo microevolution of MTBC isolates from drug-susceptible to MDR, and from MDR to extensively-drug resistant (XDR). In addition, they found that the katG S315T isoniazid and rpoB S450L rifampicin resistance mutations were dominant across the different MTBC lineages. CONCLUSIONS: Our molecular epidemiological analyses identified the spread of MDR-TB to Ireland from other jurisdictions and its potential to evolve to XDR-TB.


Assuntos
Tuberculose Extensivamente Resistente a Medicamentos/epidemiologia , Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Mycobacterium tuberculosis/genética , Adulto , Tuberculose Extensivamente Resistente a Medicamentos/transmissão , Feminino , Genoma Bacteriano , Genótipo , Humanos , Irlanda/epidemiologia , Masculino , Epidemiologia Molecular , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Sequenciamento Completo do Genoma
5.
Support Care Cancer ; 23(7): 2079-87, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25533581

RESUMO

PURPOSE: Febrile neutropenia remains a common, life-threatening complication of chemotherapy in paediatric oncology. Delays in institution of empiric antibiotics have been identified at tertiary and regional centres caring for these patients and associated with decreased survival. Our objective was to reduce the time to administration of empiric antibiotics to less than 60 min from the time of presentation to hospital. METHODS: A retrospective study of the records of oncology patients presenting to the emergency department of a tertiary hospital over a 3-month period was performed and time to first antibiotic administration recorded. Potential causes of delay in commencement of antibiotics were identified and an algorithm-based approach to the management of fever in immunocompromised children developed and implemented. Follow-up evaluation data were collected at 12 and 60 months post-intervention. Causes of delay in commencement of antibiotics at regional hospitals that share care with the tertiary hospital were identified through questionnaires, interviews and focus groups, involving patients and medical and nursing staff. The impact of the introduction of the algorithm at one peripheral hospital was evaluated. RESULTS: The mean time to empiric antibiotics was reduced from 148 min (95% confidence interval (CI) 81-216) at baseline to 76 min (95% CI 50-101) at 12 months post-intervention and sustained at 65 min (95% CI 52-77) 5 years after the intervention. At the peripheral hospital, mean time to antibiotic delivery was reduced from 221 min (95% CI 114-328) to 65 min (95% CI 42-87) at 12 months after the intervention. CONCLUSION: The introduction of the guideline, with teaching and support for staff and parents, resulted in an improvement in practice, meeting international guidelines and achieving sustained results at 5 years after introduction at a tertiary hospital. The guideline has been shown to be feasible and effective at a regional hospital.


Assuntos
Antibacterianos/administração & dosagem , Neutropenia Febril Induzida por Quimioterapia/diagnóstico , Neutropenia Febril Induzida por Quimioterapia/tratamento farmacológico , Algoritmos , Criança , Auditoria Clínica , Tomada de Decisões , Esquema de Medicação , Humanos , Neoplasias/sangue , Neoplasias/tratamento farmacológico , Estudos Retrospectivos , Inquéritos e Questionários
7.
Ir Med J ; 107(3): 74-7, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24757889

RESUMO

Annual seasonal influenza vaccine is recommended for all health care workers (HCWs) in Ireland. For the 2011/2012 influenza season, information was collected on influenza vaccination uptake among HCWs employed in Health Service Executive (HSE)-funded hospitals (primarily acute) and of nursing homes (NHs) and also among NH long-term and short-term respite care residents. Forty-five hospitals (80%) and 120 NHs (75%) provided uptake data. Nationally, influenza vaccine uptake among hospital employed HCWs was estimated to be 18% and 14% among HCWs in NHs; in NHs vaccine uptake among long-term care residents was estimated to 88%. These findings highlight the continued low uptake among HCWs of all categories and demonstrate the need for sustained measures to improve uptake rates.


Assuntos
Pessoal de Saúde/estatística & dados numéricos , Programas de Imunização/organização & administração , Vacinas contra Influenza/uso terapêutico , Influenza Humana/prevenção & controle , Assistência de Longa Duração , Adulto , Idoso , Feminino , Fidelidade a Diretrizes/estatística & dados numéricos , Necessidades e Demandas de Serviços de Saúde , Hospitais/estatística & dados numéricos , Humanos , Irlanda , Assistência de Longa Duração/métodos , Assistência de Longa Duração/estatística & dados numéricos , Masculino , Casas de Saúde/estatística & dados numéricos , Vacinação/métodos
8.
Paediatr Drugs ; 15(6): 459-71, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23925711

RESUMO

The success of paediatric liver transplantation is attributed to improved surgical techniques and the advent of calcineurin inhibitor-based immunosuppression. Acute rejection (AR) rarely results in graft loss with calcineurin inhibitor immunosuppressive regimens, and the advent of newer agents like interleukin (IL)-2 receptor antibodies. The latter have the benefit of reducing the incidence of AR further and may be of use in patients who are susceptible to recurrent AR, were retransplanted for graft rejection or are in a steroid-sparing regimen. A total of 60 % of all paediatric liver transplants result in AR; however, there is a 75 % response rate to initial steroid therapy. Steroid therapy remains the mainstay of initial AR management, coupled with an increase in baseline immunosuppression. Steroid-resistant rejection (SRR), previously an immediate indication for potent anti-lymphocyte preparations, is now effectively treated with chimeric or humanised IL-2 receptor monoclonal antibodies. Recurrent AR can be treated by adding adjuvant immunosuppressive agents such as mycophenolate mofetil (MMF) or sirolimus. Studies have also demonstrated the efficacy of MMF as rescue therapy for SRR. Anti-lymphocyte preparations such as anti-thymocyte globulin (ATG) and OKT3 are rarely used in SRR but may be of use as rescue therapy for severe SRR. The challenges of the management of AR remain in the management of recurrent AR and SRR. We discuss the pathogenesis, diagnosis and management of AR, including prevention, and specific management of AR and SRR based on current evidence and our own experience at the King's College Paediatric Liver, Gastroenterology and Nutrition Centre in London.


Assuntos
Corticosteroides/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Transplante de Fígado , Doença Aguda , Quimiorradioterapia Adjuvante , Criança , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/tratamento farmacológico , Rejeição de Enxerto/imunologia , Humanos , Quimioterapia de Manutenção
10.
Chromosoma ; 121(3): 221-34, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22349693

RESUMO

Polycomb repressive complex 2 (PRC2) is a conserved multisubunit enzyme that methylates histone H3 on lysine-27. This chromatin modification is a hallmark of target genes transcriptionally silenced by the Polycomb system. At its core, PRC2 activity depends upon the SET domain active site of its catalytic subunit, EZH2, as well as critical stimulatory inputs from noncatalytic subunits, especially EED and SU(Z)12. We review recent progress on this core PRC2 machinery, including key features of the active site, control mechanisms that operate via EZH2 phosphorylation, and subunit elements and architectures that influence PRC2 function. Among these, we highlight work identifying an EED regulatory site that enables PRC2 to bind pre-existing methylated H3-K27 and stimulate enzyme output. These advances illuminate basic inner workings of PRC2 and also provide insights that could aid design of PRC2 inhibitors. The chromatin landscape that PRC2 encounters in vivo is decorated with many histone modifications that accompany active transcription, such as H3-K4 methylation. It has long been assumed that these "active" modifications oppose PRC2 at some level but, until recently, mechanisms of this antagonistic cross-talk have been elusive. We discuss new findings that illuminate how H3-K4 and H3-K36 methylation, H3-K27 acetylation, and H3-S28 phosphorylation each exert a negative impact on PRC2 function. The emerging picture presents PRC2 as a cooperative multipart machine, intricately outfitted to sense and respond to the local chromatin environment and other cues. This PRC2 design ensures flexibility and fine tuning of its fundamental gene silencing roles in diverse biological contexts.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Proteínas de Drosophila/fisiologia , Histona-Lisina N-Metiltransferase/fisiologia , Proteínas Nucleares/fisiologia , Proteínas Repressoras/fisiologia , Fatores de Transcrição/fisiologia , Acetilação , Animais , Domínio Catalítico , Montagem e Desmontagem da Cromatina , Quinases Ciclina-Dependentes/metabolismo , Drosophila melanogaster , Proteína Potenciadora do Homólogo 2 de Zeste , Regulação da Expressão Gênica , Histonas/metabolismo , Humanos , Metilação , Complexo Repressor Polycomb 2 , Proteínas do Grupo Polycomb , Estrutura Terciária de Proteína , Subunidades Proteicas/metabolismo , Tirosina/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Genetics ; 188(3): 753-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21555395

RESUMO

Functional diversification across the left/right axis is a common feature of many nervous systems. The genetic programs that control left/right asymmetric neuron function and gene expression in the nervous system are, however, poorly understood. We describe here the molecular characterization of two phenotypically similar mutant Caenorhabditis elegans strains in which left/right asymmetric gene expression programs of two gustatory neurons, called ASEL and ASER, are disrupted such that the differentiation program of the ASER neuron is derepressed in the ASEL neuron. We show that in one mutant strain the LIM homeobox gene lim-6 is defective whereas in another strain a novel member of a nematode-specific, fast-evolving family of C2H2 zinc-finger transcription factors, lsy-27, is mutated, as revealed by whole-genome sequencing. lsy-27 is broadly and exclusively expressed in the embryo and acts during the initiation, but not during the maintenance phase of ASE asymmetry control to assist in the initiation of lim-6 expression.


Assuntos
Padronização Corporal/genética , Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Diferenciação Celular/genética , Embrião não Mamífero/metabolismo , Proteínas com Homeodomínio LIM/genética , Neurônios/metabolismo , Fatores de Transcrição/genética , Animais , Sequência de Bases , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Embrião não Mamífero/citologia , Regulação da Expressão Gênica no Desenvolvimento , Genes Reporter , Proteínas com Homeodomínio LIM/metabolismo , Dados de Sequência Molecular , Mutação , Neurônios/citologia , Filogenia , Fatores de Transcrição/metabolismo , Transcrição Gênica , Dedos de Zinco/genética
12.
Genetics ; 186(4): 1497-502, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20923973

RESUMO

Left/right asymmetrically expressed genes permit an animal to perform distinct tasks with the right vs. left side of its brain. Once established during development, lateralized gene expression patterns need to be maintained during the life of the animal. We show here that a histone modifying complex, composed of the LSY-12 MYST-type histone acetyltransferase, the ING-family PHD domain protein LSY-13, and PHD/bromodomain protein LIN-49, is required to first initiate and then actively maintain lateralized gene expression in the gustatory system of the nematode Caenorhabditis elegans. Similar defects are observed upon postembryonic removal of two C2H2 zinc finger transcription factors, die-1 and che-1, demonstrating that a combination of transcription factors, which recognize DNA in a sequence-specific manner, and a histone modifying enzyme complex are responsible for inducing and maintaining neuronal laterality.


Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Lateralidade Funcional , Histona Acetiltransferases/fisiologia , Neurônios/fisiologia , Animais , Caenorhabditis elegans/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Complexos Multiproteicos/fisiologia , Fatores de Transcrição , Dedos de Zinco
13.
J Bone Joint Surg Br ; 91(4): 540-4, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19336819

RESUMO

The Thomas splint is a common piece of equipment in emergency departments and orthopaedic units in hospitals worldwide. Its basic design has changed little since its first description by Hugh Owen Thomas was published in 1875. We have reviewed the origins of the Thomas splint as a means of correction of deformities of the lower limb and its evolution through both World Wars into an essential item for the management of trauma of the lower limb.


Assuntos
Fixação de Fratura/história , Ortopedia/história , Contenções/história , Desenho de Equipamento , Fixação de Fratura/instrumentação , História do Século XIX , História do Século XX , Reino Unido
14.
Genetics ; 181(4): 1679-86, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19189954

RESUMO

We apply here comparative genome hybridization as a novel tool to identify the molecular lesion in two Caenorhabditis elegans mutant strains that affect a neuronal cell fate decision. The phenotype of the mutant strains resembles those of the loss-of-function alleles of the cog-1 homeobox gene, an inducer of the fate of the gustatory neuron ASER. We find that both lesions map to the cis-regulatory control region of cog-1 and affect a phylogenetically conserved binding site for the C2H2 zinc-finger transcription factor CHE-1, a previously known regulator of cog-1 expression in ASER. Identification of this CHE-1-binding site as a critical regulator of cog-1 expression in the ASER in vivo represents one of the rare demonstrations of the in vivo relevance of an experimentally determined or predicted transcription-factor-binding site. Aside from the mutationally defined CHE-1-binding site, cog-1 contains a second, functional CHE-1-binding site, which in isolation is sufficient to drive reporter gene expression in the ASER but in an in vivo context is apparently insufficient for promoting appropriate ASER expression. The cis-regulatory control regions of other ASE-expressed genes also contain ASE motifs that can promote ASE neuron expression when isolated from their genomic context, but appear to depend on multiple ASE motifs in their normal genomic context. The multiplicity of cis-regulatory elements may ensure the robustness of gene expression.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Proteínas de Homeodomínio/genética , Mutação , Neurogênese/genética , Elementos Reguladores de Transcrição/genética , Animais , Sequência de Bases , Diferenciação Celular/genética , Genes Homeobox , Modelos Biológicos , Dados de Sequência Molecular , Mutação/fisiologia , Neurônios/fisiologia , Homologia de Sequência do Ácido Nucleico , Fatores de Transcrição/genética
15.
J R Army Med Corps ; 155(2): 124-9, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20095180

RESUMO

Scoring systems for both trauma and intensive care patients have been widely used since the 1960's. This article will introduce several scoring systems currently in use and discuss their potential use for military ICU patients.


Assuntos
Unidades de Terapia Intensiva/organização & administração , Medicina Militar/organização & administração , Índices de Gravidade do Trauma , Ferimentos e Lesões/diagnóstico , APACHE , Escala Resumida de Ferimentos , Humanos , Militares , Triagem/métodos , Reino Unido
16.
Ir Med J ; 101(7): 221-2, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18807816

RESUMO

Under the Road Traffic Act, 2006 handheld mobile phone use whilst driving is an offence liable to a fine and penalty points. The aim of this study was to determine whether there has been a change in driver behaviour following the introduction of this legislation. This study found that 2.3% of drivers were still using a handheld mobile phone.


Assuntos
Acidentes de Trânsito/legislação & jurisprudência , Condução de Veículo/legislação & jurisprudência , Automóveis/legislação & jurisprudência , Telefone Celular/legislação & jurisprudência , Segurança/legislação & jurisprudência , Acidentes de Trânsito/prevenção & controle , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Irlanda , Masculino , Projetos Piloto
17.
Nat Methods ; 5(10): 865-7, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18677319

RESUMO

Identification of the molecular lesion in Caenorhabditis elegans mutants isolated through forward genetic screens usually involves time-consuming genetic mapping. We used Illumina deep sequencing technology to sequence a complete, mutant C. elegans genome and thus pinpointed a single-nucleotide mutation in the genome that affects a neuronal cell fate decision. This constitutes a proof-of-principle for using whole-genome sequencing to analyze C. elegans mutants.


Assuntos
Alelos , Caenorhabditis elegans/genética , Genoma Helmíntico , Mutação , Animais , DNA de Helmintos/genética , Polimorfismo de Nucleotídeo Único
18.
Eye (Lond) ; 22(5): 684-6, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17417623

RESUMO

AIMS: To report the use of ketamine sedation as an alternative anaesthetic method for babies undergoing treatment for retinopathy of prematurity (ROP). METHODS: All babies who underwent treatment for ROP over a 2-year period were included in this study. The babies preoperative weight, medical condition, and ventilation status was recorded. Data were collected on their ventilation status pre-, intra-, and postprocedure. Any change in their cardiac or respiratory status during or in the subsequent 3 days following the treatment was noted. RESULTS: Eleven babies, 22 eyes, required treatment over this period. The procedure was well tolerated with only three babies having intraoperative complications, which all resolved spontaneously. Two babies had postoperative complications requiring additional ventilation. In no case was the procedure abandoned owing to anaesthetic complications. CONCLUSIONS: The use of ketamine sedation allows the laser to be performed in a ward setting and avoids the potential risk of general anaesthesia and inter- and intra-hospital transfer. It has been found to produce few intra- or postoperative complications for the infant, while providing satisfactory conditions for the treatment of ROP.


Assuntos
Anestésicos Dissociativos , Sedação Consciente/métodos , Ketamina , Retinopatia da Prematuridade/cirurgia , Anestésicos Dissociativos/efeitos adversos , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Ketamina/efeitos adversos , Masculino , Ventilação Pulmonar , Doenças Retinianas/cirurgia
20.
Genetics ; 176(4): 2109-30, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17717195

RESUMO

We describe here the results of genetic screens for Caenorhabditis elegans mutants in which a single neuronal fate decision is inappropriately executed. In wild-type animals, the two morphologically bilaterally symmetric gustatory neurons ASE left (ASEL) and ASE right (ASER) undergo a left/right asymmetric diversification in cell fate, manifested by the differential expression of a class of putative chemoreceptors and neuropeptides. Using single cell-specific gfp reporters and screening through a total of almost 120,000 haploid genomes, we isolated 161 mutants that define at least six different classes of mutant phenotypes in which ASEL/R fate is disrupted. Each mutant phenotypic class encompasses one to nine different complementation groups. Besides many alleles of 10 previously described genes, we have identified at least 16 novel "lsy" genes ("laterally symmetric"). Among mutations in known genes, we retrieved four alleles of the miRNA lsy-6 and a gain-of-function mutation in the 3'-UTR of a target of lsy-6, the cog-1 homeobox gene. Using newly found temperature-sensitive alleles of cog-1, we determined that a bistable feedback loop controlling ASEL vs. ASER fate, of which cog-1 is a component, is only transiently required to initiate but not to maintain ASEL and ASER fate. Taken together, our mutant screens identified a broad catalog of genes whose molecular characterization is expected to provide more insight into the complex genetic architecture of a left/right asymmetric neuronal cell fate decision.


Assuntos
Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/genética , Genes de Helmintos , Alelos , Animais , Animais Geneticamente Modificados , Sequência de Bases , Padronização Corporal/genética , Caenorhabditis elegans/citologia , Morte Celular/genética , Mapeamento Cromossômico , Primers do DNA/genética , DNA de Helmintos/genética , Genes Homeobox , Genes Reporter , Canais Iônicos/genética , Dados de Sequência Molecular , Mutação , Neurônios/citologia , Fenótipo , Homologia de Sequência do Ácido Nucleico
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