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1.
J Psychiatr Res ; 130: 89-96, 2020 11.
Article in English | MEDLINE | ID: mdl-32798774

ABSTRACT

OBJECTIVE: Effectiveness of evidence-based psychotherapy (EBP) for PTSD can vary based on gender and trauma type, with poorer outcomes for men and sexual traumas. Among veterans receiving EBPs for PTSD, the effects of the interaction between gender and military sexual trauma (MST) on treatment outcome are unclear. This study examined how gender and MST impact PTSD symptoms following cognitive processing therapy (CPT) and prolonged exposure (PE). METHOD: We conducted a national, retrospective cohort study of all post 9/11 veterans who had a PTSD diagnosis from 10/2001-9/2017 at VHA facilities and >1 psychotherapy visit. Inclusion criteria included completion of ≥8 CPT/PE sessions and pre- and post-treatment PCL (N = 9711). Mixed-effects linear regression models were conducted, separately by treatment, to examine associations between changes in PTSD symptoms and gender, MST, and their interactions with time. RESULTS: For both treatments, there were no significant differences in pre-treatment PCL by gender or MST, and PCL decreased significantly over time. In adjusted models, only the gender by time interaction on pre-to-post-CPT change was significant (p < .001); the decrease in women's PCL was 2.67 points greater, compared to men. CONCLUSIONS: Women veterans demonstrated greater reductions in PTSD symptoms from CPT. There were no differences by gender for PE, suggesting men and women veterans benefit similarly. Results suggest outcomes may be impacted by gender socialization when utilizing certain cognitive behavioral techniques. MST, regardless of gender, did not impact PTSD outcomes for either treatment. Both CPT and PE may thus be effective for veterans irrespective of MST history.


Subject(s)
Cognitive Behavioral Therapy , Military Personnel , Sex Offenses , Stress Disorders, Post-Traumatic , Veterans , Female , Humans , Male , Retrospective Studies , Sexual Trauma , Stress Disorders, Post-Traumatic/epidemiology , Stress Disorders, Post-Traumatic/therapy
2.
Rev. Soc. Boliv. Pediatr ; 47(2): 98-99, 2008.
Article in Spanish | LILACS | ID: lil-652453

ABSTRACT

La Neisseria gonorrhoeae (NG) es un diplococo Gram negativo oxidasa positivo y productor de beta-lactamasa. Existen alrededor de 70 cepas diferentes y sólo los humanos son infectadas por estos agentes.


Subject(s)
Infant, Newborn , Infections , Infection Control
3.
J Neurobiol ; 60(3): 275-88, 2004 Sep 05.
Article in English | MEDLINE | ID: mdl-15281067

ABSTRACT

Serotonin (5HT) plays major roles in the physiological regulation of many behavioral processes, including sleep, feeding, and mood, but the genetic mechanisms by which serotonergic neurons arise during development are poorly understood. In the present study, we have investigated the development of serotonergic neurons in the zebrafish. Neurons exhibiting 5HT-immunoreactivity (5HT-IR) are detected from 45 h postfertilization (hpf) in the ventral hindbrain raphe, the hypothalamus, pineal organ, and pretectal area. Tryptophan hydroxylases encode rate-limiting enzymes that function in the synthesis of 5HT. As part of this study, we cloned and analyzed a novel zebrafish tph gene named tphR. Unlike two other zebrafish tph genes (tphD1 and tphD2), tphR is expressed in serotonergic raphe neurons, similar to tph genes in mammalian species. tphR is also expressed in the pineal organ where it is likely to be involved in the pathway leading to synthesis of melatonin. To better understand the signaling pathways involved in the induction of the serotonergic phenotype, we analyzed tphR expression and 5HT-IR in embryos in which either Hh or Fgf signals are abrogated. Hindbrain 5HT neurons are severely reduced in mutants lacking activity of either Ace/Fgf8 or the transcription factor Noi/Pax2.1, which regulates expression of ace/fgf8, and probably other genes encoding signaling proteins. Similarly, serotonergic raphe neurons are absent in embryos lacking Hh activity confirming a conserved role for Hh signals in the induction of these cells. Conversely, over-activation of the Hh pathway increases the number of serotonergic neurons. As in mammals, our results are consistent with the transcription factors Nk2.2 and Gata3 acting downstream of Hh activity in the development of serotonergic raphe neurons. Our results show that the pathways involved in induction of hindbrain serotonergic neurons are likely to be conserved in all vertebrates and help establish the zebrafish as a model system to study this important neuronal class.


Subject(s)
Fibroblast Growth Factors/physiology , Gene Expression Regulation, Developmental , Neurons/metabolism , Raphe Nuclei/cytology , Trans-Activators/physiology , Zebrafish Proteins/metabolism , Animals , Animals, Genetically Modified , Base Sequence , Cloning, Molecular/methods , Embryo, Nonmammalian , Enzyme Inhibitors/pharmacology , Fertilization , Green Fluorescent Proteins , Hedgehog Proteins , Homeodomain Proteins/metabolism , In Situ Hybridization/methods , LIM-Homeodomain Proteins , Luminescent Proteins/metabolism , Nerve Tissue Proteins/metabolism , Pyrroles/pharmacology , Raphe Nuclei/embryology , Rod Opsins/metabolism , Sequence Alignment/methods , Serotonin/metabolism , Signal Transduction/physiology , Time Factors , Trans-Activators/genetics , Trans-Activators/metabolism , Transcription Factors , Tryptophan Hydroxylase/genetics , Tryptophan Hydroxylase/metabolism , Veratrum Alkaloids/pharmacology , Zebrafish/embryology , Zebrafish Proteins/genetics
4.
Development ; 128(4): 571-80, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11171340

ABSTRACT

Rhombomeres are segmental units of the developing vertebrate hindbrain that underlie the reiterated organisation of cranial neural crest migration and neuronal differentiation. valentino (val), a zebrafish homologue of the mouse bzip transcription factor-encoding gene, kreisler, is required for segment boundary formation caudal to rhombomere 4 (r4). val is normally expressed in r5/6 and is required for cells to contribute to this region. In val(-) mutants, rX, a region one rhombomere in length and of mixed identity, lies between r4 and r7. While a number of genes involved in establishing rhombomeric identity are known, it is still largely unclear how segmental integrity is established and boundaries are formed. Members of the Eph family of receptor tyrosine kinases and their ligands, the ephrins, are candidates for functioning in rhombomere boundary formation. Indeed, expression of the receptor ephB4a coincides with val in r5/6, whilst ephrin-B2a, which encodes a ligand for EphB4a, is expressed in r4 and r7, complementary to the domain of val expression. Here we show that in val(-) embryos, ephB4a expression is downregulated and ephrin-B2a expression is upregulated between r4 and r7, indicating that Val is normally required to establish the mutually exclusive expression domains of these two genes. We show that juxtaposition of ephB4a-expressing cells and ephrin-B2a-expressing cells in the hindbrain leads to boundary formation. Loss of the normal spatial regulation of eph/ephrin expression in val mutants correlates not only with absence of boundaries but also with the inability of mutant cells to contribute to wild-type r5/6. Using a genetic mosaic approach, we show that spatially inappropriate Eph signalling underlies the repulsion of val(-) cells from r5/6. We propose that Val controls eph expression and that interactions between EphB4a and Ephrin-B2a mediate cell sorting and boundary formation in the segmenting caudal hindbrain.


Subject(s)
Gene Expression Regulation, Developmental , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Rhombencephalon/cytology , Rhombencephalon/embryology , Signal Transduction , Zebrafish Proteins , Zebrafish/embryology , Animals , Cell Differentiation , Cell Division , Cell Lineage , Ephrin-B2 , Gene Deletion , Immunohistochemistry , In Situ Hybridization , MafB Transcription Factor , Membrane Proteins/genetics , Microinjections , Mosaicism/genetics , Nerve Tissue Proteins/genetics , Phenotype , Protein Binding , RNA, Messenger/metabolism , Receptor Protein-Tyrosine Kinases/genetics , Receptor Protein-Tyrosine Kinases/metabolism , Receptor, EphB4 , Receptors, Eph Family , Recombinant Fusion Proteins
5.
Dev Biol ; 226(2): 220-30, 2000 Oct 15.
Article in English | MEDLINE | ID: mdl-11023682

ABSTRACT

Rohon Beard (RB) cells are embryonic primary sensory neurons that are removed by programmed cell death during larval development in zebrafish. RB somatosensory functions are taken over by neurons of the dorsal root ganglia (DRG), suggesting that RB cell death may be triggered by the differentiation of these ganglia, as has been proposed to be the case in Xenopus. However, here we show that the timing of RB cell death correlates with reduced expression of trkC1, the receptor for neurotrophin NT-3, but not with the appearance of DRG, which differentiate only after most RB cells die. trkC1 is expressed in subpopulations of RB neurons during development, and cell death is initiated only in trkC1-negative neurons, suggesting a role for TrkC1 and its ligand, NT-3, in RB cell survival. In support of this, antibodies that deplete NT-3 induce RB cell death while exogenous application of NT-3 reduces death. In addition, we show that RB cell death can be prevented using a caspase inhibitor, zVADfmk, showing that during normal development, RB cells die by a caspase-dependent programmed cell death pathway possibly triggered by reduced signaling via TrkC1.


Subject(s)
Apoptosis/physiology , Nerve Tissue Proteins/physiology , Neurons, Afferent/cytology , Neurotrophin 3/physiology , Receptor, trkC/physiology , Zebrafish/growth & development , Animals , Apoptosis/drug effects , Caspases/physiology , Cell Differentiation , Cells, Cultured , Ganglia, Spinal/cytology , In Situ Nick-End Labeling , Nerve Tissue Proteins/drug effects , Neurons, Afferent/classification , Neurons, Afferent/drug effects , Neurotrophin 3/pharmacology , Receptor, trkC/drug effects , Signal Transduction , Zebrafish/anatomy & histology
7.
Hear Res ; 143(1-2): 171-81, 2000 May.
Article in English | MEDLINE | ID: mdl-10771194

ABSTRACT

The numbers and positions of cells undergoing cell death and proliferation in the neuromasts of 10 day old zebrafish larvae were assessed to investigate the ability of supporting cells to differentiate into hair cells. Evaluations of cell death and proliferation showed that a subpopulation of cells located in the centre of the neuromast undergo cell death, and a different subpopulation located at the periphery proliferate. This suggests that cell death of hair cells and proliferation of mantle supporting cells occurs as part of normal development, creating constant turnover of hair cells. We show that the caspase inhibitor zVADfmk reduces cell death while the aminoglycoside neomycin specifically induces an increased amount of cell death in the central population of cells. Both of these treatments affect the rate of proliferation of the peripheral subpopulation of cells in the neuromast suggesting that a feedback mechanism occurs regulating cell death and proliferation. We propose that the dying population of cells are hair cells and the proliferating cells are 'mantle' supporting cells, which is in agreement with previous observations suggesting that supporting cells can give rise to hair cells following hair cell death.


Subject(s)
Sense Organs/cytology , Zebrafish/growth & development , Amino Acid Chloromethyl Ketones/pharmacology , Animals , Apoptosis , Cell Death/drug effects , Cell Death/physiology , Cell Differentiation/physiology , Cell Division/physiology , Cell Movement , Cysteine Proteinase Inhibitors/pharmacology , Hair Cells, Auditory/cytology , Larva/cytology , Larva/physiology , Larva/ultrastructure , Neomycin/pharmacology , Sense Organs/physiology , Sense Organs/ultrastructure
8.
Development ; 127(8): 1703-13, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10725246

ABSTRACT

Somite formation involves the establishment of a segmental prepattern in the presomitic mesoderm, anteroposterior patterning of each segmental primordium and formation of boundaries between adjacent segments. How these events are co-ordinated remains uncertain. In this study, analysis of expression of zebrafish mesp-a reveals that each segment acquires anteroposterior regionalisation when located in the anterior presomitic mesoderm. Thus anteroposterior patterning is occurring after the establishment of a segmental prepattern in the paraxial mesoderm and prior to somite boundary formation. Zebrafish fss(-), bea(-), des(-) and aei(-) embryos all fail to form somites, yet we demonstrate that a segmental prepattern is established in the presomitic mesoderm of all these mutants and hox gene expression shows that overall anteroposterior patterning of the mesoderm is also normal. However, analysis of various molecular markers reveals that anteroposterior regionalisation within each segment is disturbed in the mutants. In fss(-), there is a loss of anterior segment markers, such that all segments appear posteriorized, whereas in bea(-), des(-) and aei(-), anterior and posterior markers are expressed throughout each segment. Since somite formation is disrupted in these mutants, correct anteroposterior patterning within segments may be a prerequisite for somite boundary formation. In support of this hypothesis, we show that it is possible to rescue boundary formation in fss(-) through the ectopic expression of EphA4, an anterior segment marker, in the paraxial mesoderm. These observations indicate that a key consequence of the anteroposterior regionalisation of segments may be the induction of Eph and ephrin expression at segment interfaces and that Eph/ephrin signalling subsequently contributes to the formation of somite boundaries.


Subject(s)
Body Patterning/physiology , Helix-Loop-Helix Motifs , Transcription Factors/metabolism , Zebrafish Proteins , Zebrafish/embryology , Amino Acid Sequence , Animals , Axis, Cervical Vertebra , Basic Helix-Loop-Helix Transcription Factors , Cleavage Stage, Ovum/physiology , Cloning, Molecular , Fetal Proteins/genetics , Fetal Proteins/metabolism , Gene Expression Regulation, Developmental , Molecular Sequence Data , Receptor Protein-Tyrosine Kinases/genetics , Receptor Protein-Tyrosine Kinases/metabolism , Receptor, EphA4 , Somites , Transcription Factors/classification , Transcription Factors/genetics , Zebrafish/genetics
9.
Genes Dev ; 13(22): 2983-95, 1999 Nov 15.
Article in English | MEDLINE | ID: mdl-10580005

ABSTRACT

The mechanisms regulating vertebrate heart and endoderm development have recently become the focus of intense study. Here we present evidence from both loss- and gain-of-function experiments that the zinc finger transcription factor Gata5 is an essential regulator of multiple aspects of heart and endoderm development. We demonstrate that zebrafish Gata5 is encoded by the faust locus. Analysis of faust mutants indicates that early in embryogenesis Gata5 is required for the production of normal numbers of developing myocardial precursors and the expression of normal levels of several myocardial genes including nkx2.5. Later, Gata5 is necessary for the elaboration of ventricular tissue. We further demonstrate that Gata5 is required for the migration of the cardiac primordia to the embryonic midline and for endodermal morphogenesis. Significantly, overexpression of gata5 induces the ectopic expression of several myocardial genes including nkx2.5 and can produce ectopic foci of beating myocardial tissue. Together, these results implicate zebrafish Gata5 in controlling the growth, morphogenesis, and differentiation of the heart and endoderm and indicate that Gata5 regulates the expression of the early myocardial gene nkx2.5.


Subject(s)
DNA-Binding Proteins/physiology , Endoderm/physiology , Gene Expression Regulation, Developmental , Heart/embryology , Transcription Factors/physiology , Xenopus Proteins , Zebrafish/genetics , Zinc Fingers/physiology , Amino Acid Sequence , Animals , DNA-Binding Proteins/genetics , Embryo, Nonmammalian/metabolism , Embryonic Development , GATA5 Transcription Factor , Heart Defects, Congenital/genetics , Homeobox Protein Nkx-2.5 , Homeodomain Proteins/biosynthesis , Homeodomain Proteins/genetics , In Situ Hybridization , Molecular Sequence Data , Morphogenesis , Muscle Proteins/biosynthesis , Muscle Proteins/genetics , Sequence Alignment , Sequence Homology, Amino Acid , Transcription Factors/genetics , Transcription, Genetic , Zebrafish/embryology , Zebrafish Proteins , Zinc Fingers/genetics
10.
Methods Mol Biol ; 97: 431-9, 1999.
Article in English | MEDLINE | ID: mdl-10443383
12.
Phys Ther ; 79(7): 642-52, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10416574

ABSTRACT

BACKGROUND AND PURPOSE: Physical therapists (PTs) and physical therapist assistants (PTAs) are susceptible to occupational musculoskeletal injuries. The purpose of this study was to examine the reported causes and prevalence of occupational musculoskeletal injuries to PTs and PTAs during a 2-year period. SUBJECTS: A questionnaire was mailed to 500 PTs and 500 PTAs randomly selected from the American Physical Therapy Association 1996 active membership list. Six hundred sixty-seven questionnaires were returned, giving a response rate of 67%. METHOD: Based on a literature review and a pilot study, an occupational injury questionnaire was constructed and mailed. Self-reports of injuries were obtained. RESULTS: Thirty-two percent of the PTs and 35% of the PTAs reported sustaining a musculoskeletal injury. The highest prevalence of injury was to the low back (62% of injured PTs and 56% of injured PTAs). The PTs reported the upper back and the wrist and hand as having the second highest prevalence (23%). The PTAs reported the upper back as having the second highest prevalence (28%). The PTs and PTAs reported making changes in their work habits of improved body mechanics, increased use of other personnel, and frequent change of work position. The majority of PTs and PTAs reported they did not limit patient contact time or area of practice after sustaining an injury. CONCLUSION AND DISCUSSION: Although PTs and PTAs are recognized to be knowledgeable in prevention and treatment of musculoskeletal injuries, they are susceptible to sustaining occupational musculoskeletal injuries because of performing labor-intensive tasks.


Subject(s)
Musculoskeletal Diseases/epidemiology , Occupational Diseases/epidemiology , Physical Therapy Modalities/statistics & numerical data , Adult , Aged , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Musculoskeletal Diseases/etiology , Musculoskeletal Diseases/prevention & control , Occupational Diseases/etiology , Occupational Diseases/prevention & control , Prevalence , United States/epidemiology , Wounds and Injuries/epidemiology , Wounds and Injuries/etiology
13.
Development ; 126(13): 2967-78, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10357940

ABSTRACT

The organizer at the midbrain-hindbrain boundary (MHB organizer) has been proposed to induce and polarize the midbrain during development. We investigate the requirement for the MHB organizer in acerebellar mutants, which lack a MHB and cerebellum, but retain a tectum, and are mutant for fgf8, a candidate inducer and polarizer. We examine the retinotectal projection in the mutants to assay polarity in the tectum. In mutant tecta, retinal ganglion cell (RGC) axons form overlapping termination fields, especially in the ventral tectum, and along both the anterior-posterior and dorsal-ventral axis of the tectum, consistent with a MHB requirement in generating midbrain polarity. However, polarity is not completely lost in the mutant tecta, in spite of the absence of the MHB. Moreover, graded expression of the ephrin family ligand Ephrin-A5b is eliminated, whereas Ephrin-A2 and Ephrin-A5a expression is leveled in acerebellar mutant tecta, showing that ephrins are differentially affected by the absence of the MHB. Some RGC axons overshoot beyond the mutant tectum, suggesting that the MHB also serves a barrier function for axonal growth. By transplanting whole eye primordia, we show that mapping defects and overshooting largely, but not exclusively, depend on tectal, but not retinal genotype, and thus demonstrate an independent function for Fgf8 in retinal development. The MHB organizer, possibly via Fgf8 itself, is thus required for midbrain polarisation and for restricting axonal growth, but other cell populations may also influence midbrain polarity.


Subject(s)
Brain/embryology , Fibroblast Growth Factors/genetics , Zebrafish/embryology , Animals , Ephrin-A2 , Ephrin-A5 , Fibroblast Growth Factor 8 , Gene Expression Regulation, Developmental , Genotype , Immunohistochemistry , In Situ Hybridization , Ligands , Membrane Proteins/genetics , Mutation , Phenotype , RNA, Messenger/metabolism , Tissue Transplantation , Transcription Factors/genetics , Zebrafish/genetics
14.
Mech Dev ; 83(1-2): 77-94, 1999 May.
Article in English | MEDLINE | ID: mdl-10381569

ABSTRACT

Eph receptor tyrosine kinases (RTK) and their ephrin ligands are involved in the transmission of signals which regulate cytoskeletal organisation and cell migration, and are expressed in spatially restricted patterns at discrete phases during embryogenesis. Loss of function mutants of Eph RTK or ephrin genes result in defects in neuronal pathfinding or cell migration. In this report we show that soluble forms of human EphA3 and ephrin-A5, acting as dominant negative inhibitors, interfere with early events in zebrafish embryogenesis. Exogenous expression of both proteins results in dose-dependent defects in somite development and organisation of the midbrain-hindbrain boundary and hindbrain. The nature of the defects as well as the distribution and timing of expression of endogenous ligands/receptors for both proteins suggest that Eph-ephrin interaction is required for the organisation of embryonic structures by coordinating the cellular movements of convergence during gastrulation.


Subject(s)
Gastrula/metabolism , Membrane Proteins/metabolism , Multigene Family/physiology , Proteins/metabolism , Animals , Cell Movement , Dose-Response Relationship, Drug , Embryo, Nonmammalian/anatomy & histology , Ephrin-A1 , Ephrin-A3 , Ephrin-A5 , Ephrin-B1 , Gene Expression Regulation, Developmental , Genes, Dominant , Humans , Kinetics , Membrane Proteins/analysis , RNA, Messenger/pharmacology , Time Factors , Zebrafish/embryology
15.
Development ; 126(14): 3067-78, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10375499

ABSTRACT

The endoderm forms the gut and associated organs, and develops from a layer of cells which emerges during gastrula stages in the vertebrate embryo. In comparison to mesoderm and ectoderm, little is known about the signals which induce the endoderm. The origin of the endoderm is intimately linked with that of mesoderm, both by their position in the embryo, and by the molecules that can induce them. We characterised a gene, zebrafish gata5, which is expressed in the endoderm from blastula stages and show that its transcription is induced by signals originating from the yolk cell. These signals also induce the mesoderm-expressed transcription factor no tail (ntl), whose initial expression coincides with gata5 in the cells closest to the blastoderm margin, then spreads to encompass the germ ring. We have characterised the induction of these genes and show that ectopic expression of activin induces gata5 and ntl in a pattern which mimics the endogenous expression, while expression of a dominant negative activin receptor abolishes ntl and gata5 expression. Injection of RNA encoding a constitutively active activin receptor leads to ectopic expression of gata5 and ntl. gata5 is activated cell-autonomously, whereas ntl is induced in cells distant from those which have received the RNA, showing that although expression of both genes is induced by a TGF-beta signal, expression of ntl then spreads by a relay mechanism. Expression of a fibroblast growth factor (eFGF) or a dominant negatively acting FGF receptor shows that ntl but not gata5 is regulated by FGF signalling, implying that this may be the relay signal leading to the spread of ntl expression. In embryos lacking both squint and cyclops, members of the nodal group of TGF-beta related molecules, gata5 expression in the blastoderm is abolished, making these factors primary candidates for the endogenous TGF-beta signal inducing gata5.


Subject(s)
Endoderm/physiology , Fibroblast Growth Factors/metabolism , Mesoderm/metabolism , Oligopeptides , T-Box Domain Proteins , Transforming Growth Factor beta/metabolism , Zebrafish Proteins , Zebrafish/embryology , Activins , Amino Acid Sequence , Animals , Base Sequence , Blastoderm/metabolism , Cloning, Molecular , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Digestive System/embryology , Digestive System/metabolism , Embryonic Induction/physiology , Fetal Proteins/genetics , Fetal Proteins/metabolism , GATA5 Transcription Factor , Gastrula , Gene Expression Regulation, Developmental , Germ Cells/physiology , Heart/embryology , Inhibins/genetics , Molecular Sequence Data , Myocardium/cytology , Myocardium/metabolism , Peptides/genetics , Polymerase Chain Reaction , Sequence Homology, Amino Acid , Signal Transduction , Tail/cytology , Tail/embryology , Tail/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Zebrafish/genetics
16.
Development ; 126(10): 2033-44, 1999 May.
Article in English | MEDLINE | ID: mdl-10207129

ABSTRACT

Eph receptor tyrosine kinases and their ligands, the ephrins, appear to lie functionally at the interface between pattern formation and morphogenesis. We review the role of Eph and ephrin signalling in the formation of segmented structures, in the control of axon guidance and cell migration and in the development of the vasculature. We address the question of how the specificity of response is achieved and discuss the specificity of ephrin-Eph interactions and the significance of structural domains in Eph receptors.


Subject(s)
Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Signal Transduction , Animals , Cell Transformation, Neoplastic , Ephrin-A1 , Humans , Morphogenesis
17.
Genes Dev ; 12(19): 3096-109, 1998 Oct 01.
Article in English | MEDLINE | ID: mdl-9765210

ABSTRACT

Somitogenesis involves the segmentation of the paraxial mesoderm into units along the anteroposterior axis. Here we show a role for Eph and ephrin signaling in the patterning of presomitic mesoderm and formation of the somites. Ephrin-A-L1 and ephrin-B2 are expressed in an iterative manner in the developing somites and presomitic mesoderm, as is the Eph receptor EphA4. We have examined the role of these proteins by injection of RNA, encoding dominant negative forms of Eph receptors and ephrins. Interruption of Eph signaling leads to abnormal somite boundary formation and reduced or disturbed myoD expression in the myotome. Disruption of Eph family signaling delays the normal down-regulation of her1 and Delta D expression in the anterior presomitic mesoderm and disrupts myogenic differentiation. We suggest that Eph signaling has a key role in the translation of the patterning of presomitic mesoderm into somites.


Subject(s)
Cleavage Stage, Ovum/physiology , Fetal Proteins/physiology , Membrane Proteins/physiology , Receptor Protein-Tyrosine Kinases/physiology , Signal Transduction , Somites/physiology , Amino Acid Sequence , Animals , Basic Helix-Loop-Helix Transcription Factors , Cell Differentiation , Cloning, Molecular , DNA-Binding Proteins/genetics , Ephrin-A5 , Ephrin-B2 , Fetal Proteins/genetics , Helix-Loop-Helix Motifs , Humans , Ligands , Membrane Proteins/genetics , Mice , Molecular Sequence Data , Nuclear Proteins , Protein Binding , Receptor Protein-Tyrosine Kinases/genetics , Receptor, EphA3 , Receptor, EphA4 , Receptor, EphB4 , Receptors, Eph Family , Transcription Factors , Zebrafish , Zebrafish Proteins
19.
Int J Dev Biol ; 42(6): 763-74, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9727832

ABSTRACT

Recent studies in early Xenopus and zebrafish embryos have demonstrated that posteriorizing, non-axial signals arising from outside the organizer (or shield) contribute to A/P patterning of the neural axis, in contradiction to the classical Spemann model in which such signals were proposed to be solely organizer derived. Our studies on the early expression of the transcription factors GATA-2 and 3 in both Xenopus and zebrafish nonneural ectoderm lend support to the existence of such non-axial signaling in the A/P axis. Thus we find that the earliest expression of GATA-2 and 3 is located in nonneural ectoderm and is strongly patterned in a graded manner along the A/P axis, being high anteriorly and absent from the most posterior regions. This results by early neurula stages in three broad zones: an anterior region which is positive for both GATA-2 and 3, a middle region which is positive for GATA-2 alone and a posterior region in which neither gene is expressed. These regions correspond to head, trunk and tail ectoderm and may represent the beginnings of functional segmentation of nonneural ectoderm, as suggested in the concept of the 'ectomere'. We find that A/P patterning of GATA expression in nonneural ectoderm may occur as early as late blastula/early gastrula stages. We investigate which posteriorizing signals might contribute to such distinct non axial ectodermal patterning in the A/P axis and provide evidence that both FGF and a Wnt family member contribute towards the final A/P pattern of GATA expression in nonneural ectoderm.


Subject(s)
Body Patterning/genetics , DNA-Binding Proteins/genetics , Ectoderm/physiology , Receptors, Growth Factor , Trans-Activators/genetics , Transcription Factors/genetics , Animals , Blastocyst , Bone Morphogenetic Protein 4 , Bone Morphogenetic Protein Receptors , Bone Morphogenetic Proteins/physiology , Embryonic Induction , Fibroblast Growth Factors/physiology , GATA2 Transcription Factor , GATA3 Transcription Factor , Gastrula , Gene Expression Regulation, Developmental , Mesoderm , Proteins/physiology , RNA/analysis , RNA/pharmacology , Receptors, Cell Surface , Receptors, Fibroblast Growth Factor , Tretinoin/pharmacology , Wnt Proteins , Wnt3 Protein , Xenopus , Xenopus Proteins , Zebrafish , Zebrafish Proteins
20.
Cell Tissue Res ; 290(2): 189-96, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9321679

ABSTRACT

Mutant analysis in the zebrafish is revealing the genes that are expressed in the early neuroepithelium and that regulate factors responsible for the guidance of commissural axons. We review work on the developing zebrafish brain illustrating the way in which territories of regulatory gene expression influence the formation and positioning of axon pathways.


Subject(s)
Axonal Transport , Brain/cytology , Brain/physiology , Cell Communication , Gene Expression Regulation , Neurons/cytology , Neurons/physiology , Transcription Factors/physiology , Zebrafish , Animals
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