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1.
Microbiol Resour Announc ; 13(7): e0038424, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-38847506

RESUMO

We provide the complete genome sequence for a novel Pseudomonas fluorescens bacteriophage named UNO-G1W1. This phage was isolated from a single ice cover sampling. The genome was sequenced on the Nanopore MinION, generated with the direct terminal repeat-phage-pipeline and polished with Illumina short reads. Sequence identity classifies the phage as an otagovirus.

2.
J Virol ; 97(5): e0044823, 2023 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-37074194

RESUMO

Coxsackievirus B3 (CVB3) is an enterovirus that causes diseases such as pancreatitis and myocarditis in humans. Approximately 10% of the CVB3 RNA genome consists of a highly structured 5' untranslated region (5' UTR) that is organized into six domains and contains a type I internal ribosome entry site (IRES). These features are common to all enteroviruses. Each RNA domain plays a vital role in translation and replication during the viral multiplication cycle. We used SHAPE-MaP chemistry to generate secondary structures of the 5' UTR from the avirulent strain CVB3/GA and the virulent strain CVB3/28. Our comparative models show how key nucleotide substitutions cause major restructuring of domains II and III of the 5' UTR in CVB3/GA. Despite these structural shifts, the molecule maintains several well-characterized RNA elements, which allows persistence of the unique avirulent strain. The results shed light on the 5' UTR regions serving as virulence determinants and those required for fundamental viral mechanisms. We used the SHAPE-MaP data to produce theoretical tertiary models using 3dRNA v2.0. These models suggest a compact conformation of the 5' UTR from the virulent strain CVB3/28 that brings critical domains into close contact. In contrast, the model of the 5' UTR from the avirulent strain CVB3/GA suggests a more extended conformation where the same critical domains are more separated. Our results suggest that the structure and orientation of RNA domains in the 5' UTR are responsible for low-efficiency translation, low viral titers, and absence of virulence observed during infection by CVB3/GA. IMPORTANCE Human enteroviruses, which include five different species and over 100 serotypes, are responsible for diseases ranging from mild respiratory infections to serious infections of pancreas, heart, and neural tissue. All enteroviral RNA genomes have a long and highly structured 5' untranslated region (5' UTR) containing an internal ribosome entry site (IRES). Major virulence determinants are located in the 5' UTR. We present RNA structure models that directly compare the 5' UTR derived from virulent and avirulent strains of the enterovirus coxsackievirus B3 (CVB3). The secondary-structure models show rearrangement of RNA domains known to be virulence determinants and conservation of structure in RNA elements known to be vital for translation and replication in the avirulent strain CVB3/GA. The tertiary-structure models reveal reorientation of RNA domains in CVB3/GA. Identifying the details of structure in these critical RNA domains will help direct antiviral approaches to this major human pathogen.


Assuntos
Infecções por Coxsackievirus , Enterovirus Humano B , RNA Viral , Humanos , Regiões 5' não Traduzidas , Infecções por Coxsackievirus/genética , Enterovirus Humano B/genética , Células HeLa , Sítios Internos de Entrada Ribossomal , Fenótipo , RNA Viral/genética , RNA Viral/metabolismo , Virulência , Fatores de Virulência
3.
Viruses ; 15(2)2023 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-36851509

RESUMO

Enterovirus-D68 (EV-D68) is a positive-sense single-stranded RNA virus within the family Picornaviridae. EV-D68 was initially considered a respiratory virus that primarily affected children. However, in 2014, EV-D68 outbreaks occurred causing the expected increase in respiratory illness cases, but also an increase in acute flaccid myelitis cases (AFM). Sequencing of 2014 outbreak isolates revealed variations in the 5' UTR of the genome compared to the historical Fermon strain. The structure of the 5' UTR RNA contributes to enterovirus virulence, including neurovirulence in poliovirus, and could contribute to neurovirulence in contemporary EV-D68 strains. In this study, the secondary and tertiary structures of 5' UTR RNA from the Fermon strain and 2014 isolate KT347251.1 are analyzed and compared. Secondary structures were determined using SHAPE-MaP and TurboFold II and tertiary structures were predicted using 3dRNAv2.0. Comparison of RNA structures between the EV-D68 strains shows significant remodeling at the secondary and tertiary levels. Notable secondary structure changes occurred in domains II, IV and V. Shifts in the secondary structure changed the tertiary structure of the individual domains and the orientation of the domains. Our comparative structural models for EV-D68 5' UTR RNA highlight regions of the molecule that could be targeted for treatment of neurotropic enteroviruses.


Assuntos
Regiões 5' não Traduzidas , Enterovirus Humano D , Infecções por Enterovirus , RNA Viral , Humanos , Antígenos Virais , Surtos de Doenças , Enterovirus Humano D/genética , Enterovirus Humano D/patogenicidade , Infecções por Enterovirus/epidemiologia , Fenótipo , RNA Viral/genética
4.
Int J STEM Educ ; 9(1): 10, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35106273

RESUMO

BACKGROUND: Designed in 2012 with a first implementation in 2013, NE STEM 4U is a professional development program for post-secondary students/undergraduates, and serves as a source of outreach, content knowledge generation, and STEM literacy for youth in grades kindergarten through 8th grade (ages 5-14). The model empowers post-secondary students as facilitators of inquiry-based learning within the context of an out-of-school time program. This study investigated the potential for replicating or 'franchising' this model by evaluating on the following: (1) Is the model replicable? And, if so, (2) what core elements are necessary for program fidelity? And (3) is there a dependency on a particular setting/participant type (e.g., a more rural or urban setting)? RESULTS: Strategic expansion of the program to different institutional types (i.e., Research 1, Research II, and a predominantly undergraduate institution), different geographical locations (i.e., rural and urban), and with various school district partners (i.e., large and small) determined that program fidelity and replicability required 4 core elements or criteria: (i) intentional programming, (ii) staff quality, (iii) effective partnerships, and (iv) program evaluation and continuous improvement. Importantly, we examined emergent themes by each site, as well as in combination (n = 16 focus group participants, n = 12 reflection surveys). These data indicated that Flexibility (21.22%), Student Engagement (i.e., Youth) (19.53%), Classroom Management (i.e., also pertaining to youth) (19.31%), and Communication (15.71%) were the themes most referenced by the post-secondary student mentors in the NE STEM 4U program, regardless of site. Finally, the YPQA results demonstrate general replication of program quality in a "franchise" location. CONCLUSIONS: These results highlight the core elements of the NE STEM 4U program for consideration of expansion (through strategic replication or 'franchising') as a possible international model. The findings and voices highlight the program's trajectory toward success into environments that expand professional development for post-secondary students, and for delivering STEM opportunities for youth. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40594-021-00320-0.

5.
J Microbiol Biol Educ ; 22(3)2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34970386

RESUMO

Developing effective assessments of student learning is a challenging task for faculty and even more difficult for those in emerging disciplines that lack readily available resources and standards. With the power of technology-enhanced education and accessible digital learning platforms, instructors are also looking for assessments that work in an online format. This article will be useful for all teachers, but especially for entry-level instructors, in addition to more mature instructors who are looking to become more well versed in assessment, who seek a succinct summary of assessment types to springboard the integration of new forms of assessment of student learning into their courses. In this paper, ten assessment types, all appropriate for face-to-face, blended, and online modalities, are discussed. The assessments are mapped to a set of bioinformatics core competencies with examples of how they have been used to assess student learning. Although bioinformatics is used as the focus of the assessment types, the question types are relevant to many disciplines.

6.
PLoS One ; 16(9): e0257404, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34506617

RESUMO

As powerful computational tools and 'big data' transform the biological sciences, bioinformatics training is becoming necessary to prepare the next generation of life scientists. Furthermore, because the tools and resources employed in bioinformatics are constantly evolving, bioinformatics learning materials must be continuously improved. In addition, these learning materials need to move beyond today's typical step-by-step guides to promote deeper conceptual understanding by students. One of the goals of the Network for Integrating Bioinformatics into Life Sciences Education (NIBSLE) is to create, curate, disseminate, and assess appropriate open-access bioinformatics learning resources. Here we describe the evolution, integration, and assessment of a learning resource that explores essential concepts of biological sequence similarity. Pre/post student assessment data from diverse life science courses show significant learning gains. These results indicate that the learning resource is a beneficial educational product for the integration of bioinformatics across curricula.


Assuntos
Biologia Computacional/métodos , Educação a Distância , Aprendizagem , Big Data , Disciplinas das Ciências Biológicas/educação , Simulação por Computador , Currículo , Escolaridade , Humanos , Modelos Lineares , Planejamento Social , Estudantes
7.
Biochem Mol Biol Educ ; 49(1): 38-45, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32744803

RESUMO

The lack of an instructional definition of bioinformatics delays its effective integration into biology coursework. Using an iterative process, our team of biologists, a mathematician/computer scientist, and a bioinformatician together with an educational evaluation and assessment specialist, developed an instructional definition of the discipline: Bioinformatics is "an interdisciplinary field that is concerned with the development and application of algorithms that analyze biological data to investigate the structure and function of biological polymers and their relationships to living systems." The field is defined in terms of its two primary foundational disciplines, biology and computer science, and its interdisciplinary nature. At the same time, we also created a rubric for assessing open-ended responses to a prompt about what bioinformatics is and how it is used. The rubric has been shown to be reliable in successive rounds of testing using both common percent agreement (89.7%) and intraclass correlation coefficient (0.620) calculations. We offer the definition and rubric to life sciences instructors to help further integrate bioinformatics into biology instruction, as well as for fostering further educational research projects.


Assuntos
Biologia Computacional/educação , Algoritmos , Disciplinas das Ciências Biológicas/educação , Biologia/educação , Currículo , Humanos , Polímeros/química , Polímeros/metabolismo
8.
Biochem Mol Biol Educ ; 48(4): 381-390, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32585745

RESUMO

While it is essential for life science students to be trained in modern techniques and approaches, rapidly developing, interdisciplinary fields such as bioinformatics present distinct challenges to undergraduate educators. In particular, many educators lack training in new fields, and high-quality teaching and learning materials may be sparse. To address this challenge with respect to bioinformatics, the Network for the Integration of Bioinformatics into Life Science Education (NIBLSE), in partnership with Quantitative Undergraduate Biology Education and Synthesis (QUBES), developed incubators, a novel collaborative process for the development of open educational resources (OER). Incubators are short-term, online communities that refine unpublished teaching lessons into more polished and widely usable learning resources. The resulting products are published and made freely available in the NIBLSE Resource Collection, providing recognition of scholarly work by incubator participants. In addition to producing accessible, high-quality resources, incubators also provide opportunities for faculty development. Because participants are intentionally chosen to represent a range of expertise in bioinformatics and pedagogy, incubators also build professional connections among educators with diverse backgrounds and perspectives and promote the discussion of practical issues involved in deploying a resource in the classroom. Here we describe the incubator process and provide examples of beneficial outcomes. Our experience indicates that incubators are a low cost, short-term, flexible method for the development of OERs and professional community that could be adapted to a variety of disciplinary and pedagogical contexts.


Assuntos
Disciplinas das Ciências Biológicas/educação , Redes Comunitárias , Biologia Computacional/educação , Currículo/normas , Aprendizagem , Ensino/normas , Humanos , Estudantes
9.
PLoS One ; 14(11): e0224288, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31738797

RESUMO

Bioinformatics, a discipline that combines aspects of biology, statistics, mathematics, and computer science, is becoming increasingly important for biological research. However, bioinformatics instruction is not yet generally integrated into undergraduate life sciences curricula. To understand why we studied how bioinformatics is being included in biology education in the US by conducting a nationwide survey of faculty at two- and four-year institutions. The survey asked several open-ended questions that probed barriers to integration, the answers to which were analyzed using a mixed-methods approach. The barrier most frequently reported by the 1,260 respondents was lack of faculty expertise/training, but other deterrents-lack of student interest, overly-full curricula, and lack of student preparation-were also common. Interestingly, the barriers faculty face depended strongly on whether they are members of an underrepresented group and on the Carnegie Classification of their home institution. We were surprised to discover that the cohort of faculty who were awarded their terminal degree most recently reported the most preparation in bioinformatics but teach it at the lowest rate.


Assuntos
Biologia/educação , Biologia Computacional/educação , Currículo , Docentes/estatística & dados numéricos , Feminino , Humanos , Masculino , Motivação , Estudantes/psicologia , Inquéritos e Questionários/estatística & dados numéricos , Estados Unidos
10.
J Virol ; 93(23)2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31534036

RESUMO

Enteroviral RNA genomes share a long, highly structured 5' untranslated region (5' UTR) containing a type I internal ribosome entry site (IRES). The 5' UTR is composed of stably folded RNA domains connected by unstructured RNA regions. Proper folding and functioning of the 5' UTR underlies the efficiency of viral replication and also determines viral virulence. We have characterized the structure of 5' UTR genomic RNA from coxsackievirus B3 using selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) and base-specific chemical probes in solution. Our results revealed novel structural features, including realignment of major domains, newly identified long-range interactions, and an intrinsically disordered connecting region. Together, these newly identified features contribute to a model for enteroviral 5' UTRs with type I IRES elements that links structure to function during the hierarchical processes directed by genomic RNA during viral infection.IMPORTANCE Enterovirus infections are responsible for human diseases, including myocarditis, pancreatitis, acute flaccid paralysis, and poliomyelitis. The virulence of these viruses depends on efficient recognition of the RNA genome by a large family of host proteins and protein synthesis factors, which in turn relies on the three-dimensional folding of the first 750 nucleotides of the molecule. Structural information about this region of the genome, called the 5' untranslated region (5' UTR), is needed to assist in the process of vaccine and antiviral development. This work presents a model for the structure of the enteroviral 5' UTR. The model includes an RNA element called an intrinsically disordered RNA region (IDRR). Intrinsically disordered proteins (IDPs) are well known, but correlates in RNA have not been proposed. The proposed IDRR is a 20-nucleotide region, long known for its functional importance, where structural flexibility helps explain recognition by factors controlling multiple functional states.


Assuntos
Regiões 5' não Traduzidas/genética , Enterovirus/genética , Conformação de Ácido Nucleico , RNA Viral/genética , Animais , Genômica , Humanos , Sítios Internos de Entrada Ribossomal , Picornaviridae/genética , Estabilidade de RNA , Replicação Viral
11.
PLoS One ; 13(6): e0196878, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29870542

RESUMO

Although bioinformatics is becoming increasingly central to research in the life sciences, bioinformatics skills and knowledge are not well integrated into undergraduate biology education. This curricular gap prevents biology students from harnessing the full potential of their education, limiting their career opportunities and slowing research innovation. To advance the integration of bioinformatics into life sciences education, a framework of core bioinformatics competencies is needed. To that end, we here report the results of a survey of biology faculty in the United States about teaching bioinformatics to undergraduate life scientists. Responses were received from 1,260 faculty representing institutions in all fifty states with a combined capacity to educate hundreds of thousands of students every year. Results indicate strong, widespread agreement that bioinformatics knowledge and skills are critical for undergraduate life scientists as well as considerable agreement about which skills are necessary. Perceptions of the importance of some skills varied with the respondent's degree of training, time since degree earned, and/or the Carnegie Classification of the respondent's institution. To assess which skills are currently being taught, we analyzed syllabi of courses with bioinformatics content submitted by survey respondents. Finally, we used the survey results, the analysis of the syllabi, and our collective research and teaching expertise to develop a set of bioinformatics core competencies for undergraduate biology students. These core competencies are intended to serve as a guide for institutions as they work to integrate bioinformatics into their life sciences curricula.


Assuntos
Biologia Computacional/educação , Competência Mental , Aprendizagem Baseada em Problemas , Adolescente , Adulto , Feminino , Humanos , Masculino , Estados Unidos
12.
Genome Announc ; 5(12)2017 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-28336602

RESUMO

The complete genome sequences of four Pseudomonas fluorescens bacteriophages, UNO-SLW1 to UNO-SLW4, isolated from freshwater samples, are 39,092 to 39,215 bp long. The genomes are highly similar (identity, >0.995) but dissimilar from that of Pseudomonas phage Pf-10 (the closest relative, 0.685 to 0.686 identity), with 48 to 49 protein-coding genes and 66 regulatory sites predicted.

13.
Int J STEM Educ ; 4(1): 3, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30931241

RESUMO

BACKGROUND: Many university students are becoming involved in mentoring programs, yet few studies describe the impact of mentoring on the mentor. Additionally, many studies report that students graduating from college are not prepared to enter the workforce in terms of key career skills and/or content knowledge. Herein, we examine the impact of our program, NE STEM 4U (Nebraska Science, Technology, Engineering and Math for You), in which undergraduate (UG) mentors engage K-8 youth in after-school STEM experiments. The UGs reflected upon their experiences using post-mentoring evaluations, 12- and 24-week interviews, and exit surveys. Many of the questions asked of the mentors related directly to their own professional development, such as self-evaluation of communication, organization, and problem-solving skills, while other questions related to content knowledge and reflection. RESULTS: Post-mentoring, UGs reflected on the delivery/teaching significantly more (p ≤ 0.001 for each) than other variables (i.e., their own content knowledge gains, the students' content knowledge gains, scaffolding the lessons, or overall professional growth). By analyzing the evaluations and interviews together, some significant, self-reported gains emerged. For example, 94.15% of the UG reported that the experience was beneficial to their education. Additionally, UG mentors self-reported significant gains (p ≤ 0.01 for each) moving from 12- to 24-weeks in the program in the categories of organization, STEM content knowledge, preparedness to teach, and engagement in the program. However, UG did not report significant gains in dependability. Importantly, when mentors ranked themselves at 24-weeks, they were blinded to (unaware of) the ranking they gave themselves at 12-weeks. CONCLUSIONS: This study helps to fill a gap in the literature by providing insight into the gains UG mentors report attaining after mentoring to K-8 students. These data suggest that participation by UGs in this program promoted self-reflection as well as self-reported gains related to career preparedness and STEM content knowledge.

15.
Nucleic Acids Res ; 42(15): 10112-21, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25074382

RESUMO

Coxsackievirus B3 (CV-B3) is a cardiovirulent enterovirus that utilizes a 5' untranslated region (5'UTR) to complete critical viral processes. Here, we directly compared the structure of a 5'UTR from a virulent strain with that of a naturally occurring avirulent strain. Using chemical probing analysis, we identified a structural difference between the two 5'UTRs in the highly substituted stem-loop II region (SLII). For the remainder of the 5'UTR, we observed conserved structure. Comparative sequence analysis of 170 closely related enteroviruses revealed that the SLII region lacks conservation. To investigate independent folding and function, two chimeric CV-B3 strains were created by exchanging nucleotides 104-184 and repeating the 5'UTR structural analysis. Neither the parent SLII nor the remaining domains of the background 5'UTR were structurally altered by the exchange, supporting an independent mechanism of folding and function. We show that the attenuated 5'UTR lacks structure in the SLII cardiovirulence determinant.


Assuntos
Regiões 5' não Traduzidas , Enterovirus Humano B/genética , RNA Viral/química , Enterovirus Humano B/patogenicidade , Genoma Viral , Conformação de Ácido Nucleico , Virulência
16.
PLoS One ; 8(10): e73306, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24143167

RESUMO

MUC1 is a transmembrane glycoprotein that modulates transcription via its cytoplasmic domain. We evaluated the capacity of MUC1 to regulate the global transcription of microRNAs in pancreatic cancer cells expressing MUC1. Results indicated that MUC1 regulated expression of at least 103 microRNAs. We evaluated further regulation of the microRNA transcript cluster miR-200c/141, which was among the most highly regulated microRNAs. We found that MUC1 directly interacted with ZEB1, a known transcriptional repressor of the miR-200c/141 cluster, at the promoter of miR-200c/141, and further reduced transcript production. These data indicate that signaling through MUC1 influences cancer progression by regulating transcription of microRNAs that are associated with the process of metastasis.


Assuntos
Progressão da Doença , MicroRNAs/genética , Mucina-1/metabolismo , Neoplasias Pancreáticas/patologia , Sequência de Aminoácidos , Linhagem Celular Tumoral , Proteínas de Homeodomínio/metabolismo , Humanos , Neoplasias Hepáticas/secundário , Mitose , Dados de Sequência Molecular , Mucina-1/química , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco
17.
Artigo em Inglês | MEDLINE | ID: mdl-17951826

RESUMO

In recent years, sequence database searching has been conducted through local alignment heuristics, pattern-matching, and comparison of short statistically significant patterns. While these approaches have unlocked many clues as to sequence relationships, they are limited in that they do not provide context-sensitive searching capabilities (e.g. considering pseudoknots, protein binding positions, and complementary base pairs). Stochastic grammars (hidden Markov models HMMs and stochastic context-free grammars SCFG) do allow for flexibility in terms of local context, but the context comes at the cost of increased computational complexity. In this paper we introduce a new grammar based method for searching for RNA motifs that exist within a conserved RNA structure. Our method constrains computational complexity by using a chain of topology elements. Through the use of a case study we present the algorithmic approach and benchmark our approach against traditional methods.


Assuntos
Bases de Dados de Ácidos Nucleicos , Modelos Químicos , Modelos Genéticos , RNA não Traduzido/química , RNA não Traduzido/genética , Análise de Sequência de RNA/métodos , Sequência de Bases , Simulação por Computador , Dados de Sequência Molecular , Semântica , Alinhamento de Sequência/métodos
18.
J Virol ; 81(2): 650-68, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17079314

RESUMO

Coxsackievirus B3 (CVB3) is a picornavirus which causes myocarditis and pancreatitis and may play a role in type I diabetes. The viral genome is a single 7,400-nucleotide polyadenylated RNA encoding 11 proteins in a single open reading frame. The 5' end of the viral genome contains a highly structured nontranslated region (5'NTR) which folds to form an internal ribosome entry site (IRES) as well as structures responsible for genome replication, both of which are critical for virulence. A structural model of the CVB3 5'NTR, generated primarily by comparative sequence analysis and energy minimization, shows seven domains (I to VII). While this model provides a preliminary basis for structural analysis, the model lacks comprehensive experimental validation. Here we provide experimental evidence from chemical modification analysis to determine the structure of the CVB3 5'NTR. Chemical probing results show that the theoretical model for the CVB3 5'NTR is largely, but not completely, supported experimentally. In combination with our chemical probing data, we have used the RNASTRUCTURE algorithm and sequence comparison of 105 enterovirus sequences to provide evidence for novel secondary and tertiary interactions. A comprehensive examination of secondary structure is discussed, along with new evidence for tertiary interactions. These include a loop E motif in domain III and a long-range pairing interaction that links domain II to domain V. The results of our work provide mechanistic insight into key functional elements in the cloverleaf and IRES, thereby establishing a base of structural information from which to interpret experiments with CVB3 and other picornaviruses.


Assuntos
Regiões 5' não Traduzidas/química , Regiões 5' não Traduzidas/genética , Enterovirus Humano B/genética , Genoma Viral , Aldeídos/farmacologia , Algoritmos , Sequência de Bases , Butanonas , CME-Carbodi-Imida/análogos & derivados , CME-Carbodi-Imida/farmacologia , Enterovirus Humano B/química , Humanos , Dados de Sequência Molecular , Conformação de Ácido Nucleico , RNA Viral/química , Análise de Sequência de DNA , Relação Estrutura-Atividade , Ésteres do Ácido Sulfúrico/farmacologia
19.
J Biol Chem ; 277(43): 40235-46, 2002 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-12177069

RESUMO

Regulation of the glycoprotein hormone alpha-subunit (GPHalpha) gene has been studied extensively in pituitary and placental cell lines, but little is known of the transcriptional regulators important for its ectopic expression. To investigate the molecular basis for ectopic expression, it was critical to define cis-regulatory elements and their cognate trans-acting factors that modulate promoter activity in epithelial cell types that do not normally express GPH. DNA-mediated transient expression of promoter-reporter constructs was used to identify a novel negative regulatory element located at the GPHalpha gene transcription start site. Truncation or site-directed mutagenesis of this element produced up to a 10-fold increase in promoter activity. Electrophoretic mobility shift analysis detected a protein that binds specifically to a DNA motif encompassing the cap site. Based on competitive DNA binding studies with mutated oligonucleotides, it was determined that bases from -5 to -2 and +4 to +11 are critical for protein binding. The DNA sequence flanking the transcription start site from -9 to +11 is an imperfect palindrome; consequently, this motif is referred to as the cap site diad element (CSDE) and the cognate factor as the cap site-binding protein (CSBP). CSBP activity was present at different levels in nuclear extracts prepared from a variety of cell types. Significantly, the ratio of activities exhibited by the GPHalpha promoter with a mutated CSDE compared with the promoter with a wild-type CSDE was dependent on the transfected cell line and its content of CSBP. These results indicate that a negative regulatory element centered at the GPHalpha gene cap site and its cognate DNA-binding protein make a significant contribution to the production of alpha-subunit in a variety of tumor tissues. A detailed understanding of this cis/trans pair may further suggest a mechanism to explain, at least in part, how this gene becomes activated in nonendocrine tumors.


Assuntos
Regulação da Expressão Gênica/genética , Subunidade alfa de Hormônios Glicoproteicos/genética , Gonadotropinas/genética , Sequências Reguladoras de Ácido Nucleico , Transcrição Gênica , Animais , Sequência de Bases , Primers do DNA , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Camundongos , Regiões Promotoras Genéticas
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