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Problem: Traditionally, journal editors expect individuals to complete peer reviews of submitted manuscripts on their own. Recently, a number of editors of health sciences journals have begun to support, and even espouse, the practice of group peer review (GPR). With GPR, multiple individuals work together to complete the review with permission from the journal editor. Motivated by the idea that GPR could provide a meaningful service learning experience for participants in an interprofessional educational scholarship course, we conducted three such reviews and subsequently reflected on our experience and the lessons we learned. We frame our reflections using guiding principles from the domains of peer review, professional development, and educational scholarship. Intervention: The course director arranged for manuscripts to review with the editors of three health sciences journals. Each GPR occurred during a separate weekly session of the course. Each GPR was completed using a similar set of steps, which included (a) gaining familiarity with review criteria, (b) reading aloud and discussing the manuscript's abstract as a class, (c) reading and critiquing assigned sections as individuals and then small groups, (d) building consensus and sharing notes, (e) having the course director synthesize notes into a single review for submission to the journal. Context: The course on educational scholarship involved 15 faculty representing faculty from the University of Utah's School of Medicine, College of Nursing, College of Pharmacy, College of Health, and School of Dentistry. The course director led three GPR sessions mid-way through the yearlong course. Impact: Participants' reflections indicate that GPR (a) conformed to principles of effective peer review; (b) resulted in a meaningful service learning experience within a formal professional development program, deepening understanding of core concepts of educational scholarship; and (c) represented an authentic example of engaging in educational scholarship (i.e., designing and evaluating an intervention while drawing upon and contributing to a body of shared understanding within a community of practice). Lessons Learned: Our principles-based approach to completing GPR within a professional development course on educational scholarship can serve as a model for others to follow. A rigorous, meaningful group review can occur in 1 hour using a combination of group and individual activities focused on matching review criteria to the submitted manuscript. As a result, we continue to include GPR in future offerings of this interprofessional course on educational scholarship, and we continue to study ways to optimize its value as a service learning experience.
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Manuscritos como Asunto , Revisión por Pares/métodos , BecasRESUMEN
Neural basic helix-loop helix (bHLH) transcription factors promote progenitor cell differentiation by activation of downstream target genes that coordinate neuronal differentiation. Here we characterize a neural bHLH target gene in Xenopus laevis, vexin (vxn; previously sbt1), that is homologous to human c8orf46 and is conserved across vertebrate species. C8orf46 has been implicated in cancer progression, but its function is unknown. Vxn is transiently expressed in differentiating progenitors in the developing central nervous system (CNS), and is required for neurogenesis in the neural plate and retina. Its function is conserved, since overexpression of either Xenopus or mouse vxn expands primary neurogenesis and promotes early retinal cell differentiation in cooperation with neural bHLH factors. Vxn protein is localized to the cell membrane and the nucleus, but functions in the nucleus to promote neural differentiation. Vxn inhibits cell proliferation, and works with the cyclin-dependent kinase inhibitor p27Xic1 (cdkn1b) to enhance neurogenesis and increase levels of the proneural protein Neurog2. We propose that vxn provides a key link between neural bHLH activity and execution of the neurogenic program.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Neurogénesis/genética , Proteínas de Xenopus/genética , Animales , Western Blotting , Diferenciación Celular/genética , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/metabolismo , Regulación del Desarrollo de la Expresión Génica , Hibridación in Situ , Ratones , Proteínas del Tejido Nervioso/metabolismo , Placa Neural/embriología , Placa Neural/metabolismo , Retina/embriología , Retina/metabolismo , Xenopus laevisRESUMEN
The histone methyltransferase complex PRC2 controls key steps in developmental transitions and cell fate choices; however, its roles in vertebrate eye development remain unknown. Here, we report that in Xenopus, PRC2 regulates the progression of retinal progenitors from proliferation to differentiation. We show that the PRC2 core components are enriched in retinal progenitors and downregulated in differentiated cells. Knockdown of the PRC2 core component Ezh2 leads to reduced retinal progenitor proliferation, in part due to upregulation of the Cdk inhibitor p15(Ink4b). In addition, although PRC2 knockdown does not alter eye patterning, retinal progenitor gene expression or expression of the neural competence factor Sox2, it does cause suppression of proneural bHLH gene expression, indicating that PRC2 is crucial for the initiation of neural differentiation in the retina. Consistent with this, knocking down or blocking PRC2 function constrains the generation of most retinal neural cell types and promotes a Müller glial cell fate decision. We also show that Wnt/ß-catenin signaling acting through the receptor Frizzled 5, but independent of Sox2, regulates expression of key PRC2 subunits in the developing retina. This is consistent with a role for this pathway in coordinating proliferation and the transition to neurogenesis in the Xenopus retina. Our data establish PRC2 as a regulator of proliferation and differentiation during eye development.
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Complejo Represivo Polycomb 2/metabolismo , Retina/embriología , Vía de Señalización Wnt , Proteínas de Xenopus/metabolismo , Xenopus laevis/embriología , Animales , Diferenciación Celular , Proliferación Celular , Proteína Potenciadora del Homólogo Zeste 2 , Receptores Frizzled/metabolismo , Técnicas de Silenciamiento del Gen , Histonas/metabolismo , Metilación , Complejo Represivo Polycomb 2/genética , Proteínas Represoras/metabolismo , Retina/citología , Retina/metabolismo , Proteínas de Xenopus/genéticaRESUMEN
An important step in retinal development is the positioning of progenitors within the eye field where they receive the local environmental signals that will direct their ultimate fate. Recent evidence indicates that ephrinB1 functions in retinal progenitor movement, but the signalling pathway is unclear. We present evidence that ephrinB1 signals through its intracellular domain to control retinal progenitor movement into the eye field by interacting with Xenopus Dishevelled (Xdsh), and by using the planar cell polarity (PCP) pathway. Blocking Xdsh translation prevents retinal progeny from entering the eye field, similarly to the morpholino-mediated loss of ephrinB1 (ref. 2). Overexpression of Xdsh can rescue the phenotype induced by loss of ephrinB1, and this rescue (as well as a physical association between Xdsh and ephrinB1) is completely dependent on the DEP (Dishevelled, Egl-10, Pleckstrin) domain of Xdsh. Similar gain- and loss-of-function experiments suggest that Xdsh associates with ephrinB1 and mediates ephrinB1 signalling through downstream members of the PCP pathway during eye field formation.
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Movimiento Celular , Efrina-B1/metabolismo , Fosfoproteínas/metabolismo , Retina/embriología , Xenopus laevis/embriología , Proteínas Adaptadoras Transductoras de Señales , Animales , Polaridad Celular , Proteínas Dishevelled , Retina/citología , Retina/metabolismo , Transducción de Señal , Células Madre/metabolismo , Proteínas de Xenopus , Xenopus laevis/metabolismoRESUMEN
PROBLEM: Using pass/fail (P/F) course grades may motivate students to perform well enough to earn a passing grade, giving them a false sense of competence and not motivating them to remediate deficiencies. The authors explored whether adding a not yet pass (NYP) grade to a P/F scale would promote students' mastery orientation toward learning. APPROACH: The authors captured student outcomes and data on time and cost of implementing the NYP grade in 2021 at the University of Utah School of Medicine. One cohort of medical students, who had experienced both P/F and P/NYP/F scales in years 1 and 2, completed an adapted Achievement Goal Questionnaire-Revised (AGQ-R) in fall 2021 to measure how well the P/NYP/F grading scale compared with the P/F scale promoted mastery orientation and performance orientation goals. Students who received an NYP grade provided feedback on the NYP process. OUTCOMES: Students reported that the P/NYP/F scale increased their achievement of both mastery and performance orientation goals, with significantly higher ratings for mastery orientation goals than for performance orientation goals on the AGQ-R (response rate = 124/125 [99%], P ≤ .001, effect size = 0.31). Thirty-eight students received 48 NYP grades in 7 courses during 2021, and 3 (2%) failed a subsequent course after receiving an NYP grade. Most NYP students reported the NYP process enabled them to identify and correct a deficiency (32/36 [89%]) and made them feel supported (28/36 [78%]). The process was time intensive (897 hours total for 48 NYP grades), but no extra funding was budgeted. NEXT STEPS: The findings suggest mastery orientation can be increased with an NYP grade. Implementing a P/NYP/F grading scale for years 1 and/or 2 may help students transition to programmatic assessment or no grading later in medical school, which may better prepare graduates for lifelong learning.
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Objetivos , Estudiantes de Medicina , Humanos , Facultades de Medicina , Aprendizaje , MotivaciónRESUMEN
Progenitor cells in the central nervous system must leave the cell cycle to become neurons and glia, but the signals that coordinate this transition remain largely unknown. We previously found that Wnt signaling, acting through Sox2, promotes neural competence in the Xenopus retina by activating proneural gene expression. We now report that Wnt and Sox2 inhibit neural differentiation through Notch activation. Independently of Sox2, Wnt stimulates retinal progenitor proliferation and this, when combined with the block on differentiation, maintains retinal progenitor fates. Feedback inhibition by Sox2 on Wnt signaling and by the proneural transcription factors on Sox2 mean that each element of the core pathway activates the next element and inhibits the previous one, providing a directional network that ensures retinal cells make the transition from progenitors to neurons and glia.
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Retina/embriología , Retina/fisiología , Factores de Transcripción SOXB1/fisiología , Proteínas Wnt/fisiología , Proteínas de Xenopus/fisiología , Xenopus laevis/embriología , Xenopus laevis/fisiología , beta Catenina/fisiología , Animales , Animales Modificados Genéticamente , Ciclo Celular , Diferenciación Celular , Proliferación Celular , Células Madre Embrionarias/citología , Células Madre Embrionarias/fisiología , Regulación del Desarrollo de la Expresión Génica , Modelos Biológicos , Neurogénesis/genética , Neurogénesis/fisiología , Receptores Notch/genética , Receptores Notch/fisiología , Factores de Transcripción SOXB1/genética , Transducción de Señal , Proteínas Wnt/genética , Proteínas de Xenopus/genética , Xenopus laevis/genética , beta Catenina/genéticaRESUMEN
Introduction: Assessment for learning has many benefits, but learners will still encounter high-stakes decisions about their performance throughout training. It is unknown if assessment for learning can be promoted with a combination model where scores from some assessments are factored into course grades and scores from other assessments are not used for course grading. Methods: At the University of Utah School of Medicine, year 1-2 medical students (MS) completed multiple-choice question quiz assessments and final examinations in six systems-based science courses. Quiz and final examination performance counted toward course grades for MS2017-MS2018. Starting with the MS2020 cohort, quizzes no longer counted toward course grades. Quiz, final examination, and Step 1 scores were compared between ungraded quiz and graded quiz cohorts with independent samples t-tests. Student and faculty feedback was collected. Results: Quiz performance was not different for the ungraded and graded cohorts (p = 0.173). Ungraded cohorts scored 4% higher on final examinations than graded cohorts (p ≤ 0.001, d = 0.88). Ungraded cohorts scored above the national average and 11 points higher on Step 1 compared to graded cohorts, who had scored below the national average (p ≤ 0.001, d = 0.64). During the study period, Step 1 scores increased by 2 points nationally. Student feedback was positive, and faculty felt it improved their relationship with students. Discussion: The change to ungraded quizzes did not negatively affect final examination or Step 1 performance, suggesting a combination of ungraded and graded assessments can effectively promote assessment for learning.
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During central nervous system development the timing of progenitor differentiation must be precisely controlled to generate the proper number and complement of neuronal cell types. Proneural basic helix-loop-helix (bHLH) transcription factors play a central role in regulating neurogenesis, and thus the timing of their expression must be regulated to ensure that they act at the appropriate developmental time. In the developing retina, the expression of the bHLH factor Ath5 is controlled by multiple signals in early retinal progenitors, although less is known about how these signals are coordinated to ensure correct spatial and temporal pattern of gene expression. Here we identify a key distal Xath5 enhancer and show that this enhancer regulates the early phase of Xath5 expression, while the proximal enhancer we previously identified acts later. The distal enhancer responds to Pax6, a key patterning factor in the optic vesicle, while FGF signaling regulates Xath5 expression through sequences outside of this region. In addition, we have identified an inhibitory element adjacent to the conserved distal enhancer region that is required to prevent premature initiation of expression in the retina. This temporal regulation of Xath5 gene expression is comparable to proneural gene regulation in Drosophila, whereby separate enhancers regulate different temporal phases of expression.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proteínas del Ojo , Ojo/embriología , Regulación del Desarrollo de la Expresión Génica , Proteínas de Xenopus , Xenopus laevis , Animales , Animales Modificados Genéticamente , Secuencia de Bases , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Elementos de Facilitación Genéticos , Ojo/anatomía & histología , Ojo/metabolismo , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Datos de Secuencia Molecular , Morfogénesis/fisiología , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box/genética , Factores de Transcripción Paired Box/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Retina/citología , Retina/embriología , Retina/metabolismo , Transducción de Señal/fisiología , Transgenes , Proteínas de Xenopus/genética , Proteínas de Xenopus/metabolismo , Xenopus laevis/anatomía & histología , Xenopus laevis/embriologíaRESUMEN
Introduction: Reviewing elements of a curriculum, such as courses and clerkships in medical school, is an essential part of the quality improvement process. Yet there is a gap in the literature in terms of actual rubrics for evaluating course quality in medical schools. Methods: This resource describes a course review process and rubric to evaluate course quality: A subcommittee of faculty members and students evaluates goals, content and delivery, assessment, feedback to students, grading, and student feedback for each course with the rubric. Course directors, Curriculum Committee members, and Curriculum Evaluation Subcommittee members were surveyed on their perception of the process. Results: A large majority of Curriculum Committee and Curriculum Evaluation Subcommittee members agreed that the review process was objective (100%), provided an evaluation of course quality (>95%), helped identify areas of improvement/strengths (>91%) and issues/concerns in the curriculum (>95%), helped them become more familiar with the curriculum (>90%), and was a catalyst for changes in a course (>77%). Course/clerkship directors had less agreement that the course review process was a catalyst for curriculum changes (46%) and that the process helped identify areas of improvement for a course (62%). Discussion: This curriculum evaluation process provides a resource for other institutions to use and/or modify for their own course evaluation process. All stakeholders in the review process agreed that the evaluation process was successful in identifying areas that worked and did not work in courses.
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Curriculum , Educación Médica , Humanos , Mejoramiento de la Calidad , Facultades de MedicinaRESUMEN
Progenitors in the developing central nervous system acquire neural potential and proliferate to expand the pool of precursors competent to undergo neuronal differentiation. The formation and maintenance of neural-competent precursors are regulated by SoxB1 transcription factors, and evidence that their expression is regionally regulated suggests that specific signals regulate neural potential in subdomains of the developing nervous system. We show that the frizzled (Fz) transmembrane receptor Xfz5 selectively governs neural potential in the developing Xenopus retina by regulating the expression of Sox2. Blocking either Xfz5 or canonical Wnt signaling within the developing retina inhibits Sox2 expression, reduces cell proliferation, inhibits the onset of proneural gene expression, and biases individual progenitors toward a nonneural fate, without altering the expression of multiple progenitor markers. Blocking Sox2 function mimics these effects. Rescue experiments indicate that Sox2 is downstream of Xfz5. Thus, Fz signaling can regulate the neural potential of progenitors in the developing nervous system.
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Proteínas del Ojo/metabolismo , Neuronas/citología , Retina/embriología , Transducción de Señal/fisiología , Proteínas de Xenopus/metabolismo , Animales , Animales Modificados Genéticamente , Proteínas de Unión al ADN/metabolismo , Embrión no Mamífero , Receptores Frizzled , Regulación del Desarrollo de la Expresión Génica , Hibridación in Situ , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas/metabolismo , Retina/citología , Células Madre , Proteínas Wnt , XenopusRESUMEN
The definitive retinal progenitors of the eye field are specified by transcription factors that both promote a retinal fate and control cell movements that are critical for eye field formation. However, the molecular signaling pathways that regulate these movements are largely undefined. We demonstrate that both the FGF and ephrin pathways impact eye field formation. Activating the FGF pathway before gastrulation represses cellular movements in the presumptive anterior neural plate and prevents cells from expressing a retinal fate, independent of mesoderm induction or anterior-posterior patterning. Inhibiting the FGF pathway promotes cell dispersal and significantly increases eye field contribution. ephrinB1 reverse signaling is required to promote cellular movements into the eye field, and can rescue the FGF receptor-induced repression of retinal fate. These results indicate that FGF modulation of ephrin signaling regulates the positioning of retinal progenitor cells within the definitive eye field.
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Movimiento Celular/fisiología , Embrión no Mamífero/embriología , Efrina-B1/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Retina/embriología , Xenopus laevis/embriología , Animales , Tipificación del Cuerpo/fisiología , Linaje de la Célula/fisiología , Embrión no Mamífero/citología , Embrión no Mamífero/metabolismo , Gástrula/citología , Gástrula/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Genes Reguladores/fisiología , Morfogénesis/fisiología , Fenotipo , Retina/citología , Retina/metabolismo , Transducción de Señal/fisiología , Células Madre/citología , Células Madre/metabolismo , Xenopus laevis/metabolismoRESUMEN
During central nervous system development, neurons are often born in a precise temporal sequence. Basic helix-loop-helix (bHLH) transcription factors are required for the development of specific subpopulations of neurons, but how they contribute to their ordered genesis is unclear. We show that the ability of bHLH factors to regulate the development of distinct neuronal subtypes in the Xenopus retina depends upon the timing of their function. In addition, we find that the timing of bHLH function can be regulated posttranslationally, so that bHLH factors with overlapping expression can function independently. Specifically, XNeuroD function in the retina can be inhibited by glycogen synthase kinase 3beta (GSK3beta), while Xath5 function can be inhibited by Notch. Thus, the potential of bHLH factors to regulate the development of neuronal subtypes depends upon the context in which they function.
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Proteínas de Unión al ADN/fisiología , Procesamiento Proteico-Postraduccional , Retina/embriología , Factores de Transcripción/fisiología , Proteínas de Xenopus , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proteínas Quinasas Dependientes de Calcio-Calmodulina/farmacología , Diferenciación Celular/fisiología , Resistencia a Medicamentos , Embrión no Mamífero/citología , Embrión no Mamífero/fisiología , Proteínas del Ojo/antagonistas & inhibidores , Proteínas del Ojo/farmacología , Proteínas del Ojo/fisiología , Femenino , Glucógeno Sintasa Quinasa 3 , Glucógeno Sintasa Quinasas , Proteínas de la Membrana/efectos de los fármacos , Proteínas de la Membrana/farmacología , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/fisiología , Sistema Nervioso/embriología , Receptores Notch , Retina/citología , Retina/efectos de los fármacos , Células Ganglionares de la Retina/citología , Factores de Tiempo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/farmacología , Xenopus laevis/embriologíaRESUMEN
PURPOSE: To examine the effect of apolipoprotein E (APOE) alleles on age-related macular degeneration (AMD) risk and on age at diagnosis of AMD in a large patient cohort recruited from a single center. METHODS: The frequency of APOE alleles was analyzed in 632 unrelated AMD patients and 206 unrelated controls, all of whom were of white ancestry. The presence or absence of disease symptoms in all patients and controls was based on clinical examination and/or ophthalmic records. The association with APOE was explored in the context of AMD subtypes, family history status, possible interaction with smoking, and distribution of age at diagnosis of AMD. RESULTS: The frequency of the epsilon4 allele was significantly reduced in patients compared with controls (0.10 vs. 0.14, P < or = 0.02). Gender- and age-adjusted odds ratios indicated that epsilon4-carriers have significantly lower risk of developing AMD compared to epsilon3epsilon3 subjects (OR = 0.55, 95% CI: 0.37-0.82, P = 0.004). In the cohort, AMD patients with a positive family history exhibited a significant 3.5 years earlier age at diagnosis (P = 0.001); however, APOE alleles did not appear to modulate the age at diagnosis of AMD. CONCLUSIONS: The association between the APOE-epsilon4 allele and a reduced risk of AMD was established in a large cohort with sufficient statistical power. How distinct APOE alleles affect AMD susceptibility warrants further investigation.
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Apolipoproteínas E/genética , Degeneración Macular/genética , Anciano , Alelos , Apolipoproteína E4 , Estudios de Cohortes , ADN/análisis , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Factores de RiesgoRESUMEN
The function of cone photoreceptors depends upon the formation and maintenance of outer segments, which are lost in degenerative diseases. reveal a critical role for microRNAs, specifically miR-182 and miR-183, in the maintenance of these specialized structures.
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MicroARNs/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Bastones/metabolismo , Visión Ocular/genética , Animales , HumanosRESUMEN
Fibroblast growth factor signaling plays a significant role in the developing eye, regulating both patterning and neurogenesis. Members of the Pea3/Etv4-subfamily of ETS-domain transcription factors (Etv1, Etv4, and Etv5) are transcriptional activators that are downstream targets of FGF/MAPK signaling, but whether they are required for eye development is unknown. We show that in the developing Xenopus laevis retina, etv1 is transiently expressed at the onset of retinal neurogenesis. We found that etv1 is not required for eye specification, but is required for the expression of atonal-related proneural bHLH transcription factors, and is also required for retinal neuron differentiation. Using transgenic reporters we show that the distal atoh7 enhancer, which is required for the initiation of atoh7 expression in the Xenopus retina, is responsive to both FGF signaling and etv1 expression. Thus, we conclude that Etv1 acts downstream of FGF signaling to regulate the initiation of neurogenesis in the Xenopus retina.
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Factores de Crecimiento de Fibroblastos/genética , Neurogénesis/genética , Retina/metabolismo , Factores de Transcripción/biosíntesis , Xenopus laevis/genética , Animales , Diferenciación Celular/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Neuronas/metabolismo , Retina/crecimiento & desarrollo , Transducción de Señal/genética , Factores de Transcripción/genética , Xenopus laevis/crecimiento & desarrolloRESUMEN
In a wide range of vertebrate species, the bHLH transcription factor Ath5 is tightly associated with both the initiation of neurogenesis in the retina and the genesis of retinal ganglion cells. Here, we describe at least two modes of regulating the expression of Ath5 during retinal development. We have found that a proximal cis-regulatory region of the Xenopus Ath5 gene (Xath5) is highly conserved across vertebrate species and is sufficient to drive retinal-specific reporter gene expression in transgenic Xenopus embryos. Xath5 proximal transgene expression depended upon two highly conserved bHLH factor binding sites (E-boxes) as well as bHLH factor activity in vivo. However, we found that bHLH activity was not required for expression of a longer Xath5 transgene, suggesting that additional mechanisms contribute to Xath5 expression in vivo. Consistent with this, we showed that a more distal fragment that does not include the conserved proximal region is sufficient to promote transgene expression in the developing retina. In mouse, we found that a longer fragment of the cis-regulatory region of either the mouse or Xenopus Ath5 gene was necessary for transgene expression, and that expression of a mouse Math5 (Atoh7) transgene was not dependent upon autoregulation. Thus, despite extensive conservation in the proximal region, the importance of these elements may be species dependent.
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Proteínas de Unión al ADN/metabolismo , Proteínas del Ojo/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Proteínas del Tejido Nervioso/metabolismo , Retina/embriología , Factores de Transcripción/metabolismo , Proteínas de Xenopus/metabolismo , Secuencia de Aminoácidos , Animales , Animales Modificados Genéticamente , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proteínas de Unión al ADN/genética , Embrión no Mamífero/citología , Embrión no Mamífero/metabolismo , Elementos de Facilitación Genéticos/genética , Proteínas del Ojo/genética , Regulación del Desarrollo de la Expresión Génica/genética , Secuencias Hélice-Asa-Hélice/genética , Ratones , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/genética , Retina/metabolismo , Homología de Secuencia de Aminoácido , Factores de Transcripción/genética , Proteínas de Xenopus/genética , Xenopus laevis/embriología , Xenopus laevis/metabolismoRESUMEN
The two paralogues of the Xenopus flotillin1 gene (flotillin1A and flotillin1B), which encodes a putative membrane-associated protein, were cloned from egg, cleavage, and tadpole cDNA libraries. Both mRNAs are present during oogenesis and cleavage stages. After the onset of zygotic transcription, flotillin1 transcripts are first expressed throughout the embryonic ectoderm and become enhanced in the presumptive neural ectoderm as the neural plate forms. As the neural tube forms and differentiates, flotillin1 transcripts become enriched in the dorsal half, with particularly high expression in dorsal primary neurons. At early tail bud stages, there is additional expression in the paraxial mesoderm. At late tail bud stages, flotillin1A is expressed in branchial arch mesenchyme, the overlying branchial ectoderm and in dorsal somitic mesoderm, whereas flotillin1B expression is more restricted in the dorsal neural tube and head sensory structures. This report is the first comprehensive developmental description in any animal of the expression pattern of this gene, whose protein product in several systems plays important roles in signal transduction events.