RESUMO
Fibroblast growth factor receptor (FGF-R) mRNA expression was examined in the adult rat CNS. Northern blot analysis showed a distinct 4.3 kb transcript in various CNS regions. In situ hybridization revealed widely distributed, but specific, populations of cells that express FGF-R mRNA. The most intense hybridization signals were observed in the hippocampus and in the pontine cholinergic neurons. The limbic system and brainstem nuclei, including motor nuclei, showed robust labeling. Cerebellar granule cells and spinal cord neurons were positive for FGF-R mRNA. The distribution of FGF-R mRNA differed significantly from that of NGF receptor mRNA; particularly, no hybridization signal was detected in basal forebrain cholinergic neurons. These results strongly suggest that FGF or FGF-like molecules may exert effects on specific neuronal populations in the mature CNS.
Assuntos
Sistema Nervoso Central/análise , Hibridização de Ácido Nucleico , RNA Mensageiro/análise , Receptores de Superfície Celular/análise , Sequência de Aminoácidos , Animais , Northern Blotting , DNA/genética , Fatores de Crescimento de Fibroblastos/análise , Histocitoquímica , Humanos , Camundongos , Dados de Sequência Molecular , Ratos , Receptores de Superfície Celular/genética , Receptores de Fatores de Crescimento de Fibroblastos , Distribuição TecidualRESUMO
L3/Lhx8 is a member of the LIM-homeobox gene family. Previously, we demonstrated that L3/Lhx8-null mice specifically lacked cholinergic neurons in the basal forebrain. In the present study, we conditionally suppressed L3/Lhx8 function during retinoic acid-induced neural differentiation of a murine embryonic stem (ES) cell line using an L3/Lhx8-targeted small interfering RNA (siRNA) produced by an H1.2 promoter-driven vector. Our culture conditions induced efficient differentiation of the ES cells into neurons and astrocytes, but far less efficient differentiation into oligodendrocytes. Suppression of L3/Lhx8 expression by siRNA led to a dramatic decrease in the number of cells positive for the cholinergic marker ChAT, and overexpression of L3/Lhx8 recovered this effect. However, no significant changes were observed in the number of Tuj1+ neurons and GABA+ cells. These results strongly suggest that L3/Lhx8 is a key factor in the cholinergic differentiation of murine ES cells and is involved in basal forebrain development.
Assuntos
Diferenciação Celular/fisiologia , Células-Tronco Embrionárias/metabolismo , Proteínas de Homeodomínio/fisiologia , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Diferenciação Celular/genética , Células Cultivadas , Colina O-Acetiltransferase/genética , Colina O-Acetiltransferase/metabolismo , Células-Tronco Embrionárias/citologia , Expressão Gênica , Vetores Genéticos/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Proteínas com Homeodomínio LIM , Camundongos , Mutação , Neurônios/citologia , Neurônios/metabolismo , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Prosencéfalo/citologia , Prosencéfalo/metabolismo , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição , TransfecçãoRESUMO
Fyn, a member of the Src-family protein tyrosine kinase (PTK), is an essential factor in myelination in the CNS and is involved in murine embryonic stem (ES) cell growth and differentiation. Although dysfunctions of Fyn have been comparatively studied, the gain of function by ectopic expression, especially using ES cells, has seldom been investigated. In this article, we give the first report of the involvement of Fyn alteration in the sphere formation ability of murine ES cells. First, transient transfection of Fyn hardly affected multiplication and specialization. Then, we investigated Fyn overexpression using ES cells, which stably express Fyn. As a result, altered sphere formation capability was observed in all clones stably expressing Fyn. These results may provide important information for reproduction medical treatment using ES cells.
Assuntos
Diferenciação Celular/fisiologia , Células-Tronco Embrionárias/metabolismo , Proteínas Proto-Oncogênicas c-fyn/metabolismo , Esferoides Celulares/metabolismo , Animais , Proliferação de Células , Células Cultivadas , Células-Tronco Embrionárias/citologia , Camundongos , Esferoides Celulares/citologia , TransfecçãoRESUMO
We have isolated a novel mouse gene, MFH-1 (mesenchyme fork head 1) that is related to the Drosophila fork head and rat HNF3 genes. MFH-1 encodes a distinct fork head domain that is classified into a distinct subfamily. A recombinant MFH-1 protein could bind to the HNF3 binding site. MFH-1 is expressed temporally in developing embryos, first in the non-notochordal mesoderm and later in areas of mesenchymal condensation in the trunk, head, and limbs. Our results suggest that MFH-1 might be involved in the formation of special mesenchymal tissues.
Assuntos
Proteínas de Ligação a DNA/genética , Expressão Gênica , Mesoderma/metabolismo , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Proteínas de Ligação a DNA/química , Drosophila , Embrião de Mamíferos/metabolismo , Embrião não Mamífero , Desenvolvimento Embrionário e Fetal , Fatores de Transcrição Forkhead , Fator 3-alfa Nuclear de Hepatócito , Fator 3-beta Nuclear de Hepatócito , Fator 3-gama Nuclear de Hepatócito , Camundongos , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Nucleares/genética , Reação em Cadeia da Polimerase , RNA Mensageiro/análise , Ratos , Homologia de Sequência , Fatores de Transcrição/químicaRESUMO
We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue.
Assuntos
Proteínas de Transporte/genética , Proteínas de Ligação a DNA , Família Multigênica , Proteínas do Tecido Nervoso/genética , Dedos de Zinco/genética , Sequência de Aminoácidos , Animais , Astrócitos/citologia , Proteínas de Transporte/isolamento & purificação , Sistema Nervoso Central/química , Fator de Transcrição Ikaros , Hibridização In Situ , Camundongos , Camundongos Endogâmicos ICR , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/isolamento & purificação , Sistema Nervoso Periférico/química , Ligação Proteica , RNA Mensageiro/isolamento & purificação , Homologia de Sequência de Aminoácidos , Distribuição Tecidual , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
This study shows (1) the ultrastructure of vasoactive intestinal polypeptide (VIP)-, substance P (SP)-, and neuropeptide Y (NPY)-containing nerve fibers in the walls of the cerebral arteries and (2) the relationship between these peptidergic (VIP, SP, and NPY) and catecholaminergic (CA) nerve terminals by immunohistochemistry combined with false transmitter (5-hydroxydopamine) histochemistry under the electron microscope. VIP-, SP-, and NPY-like immunoreactivity (VIPI, SPI, and NPYI) were found diffusely in the axoplasm and around the small clear vesicles in the nerve terminals. In a few cases, SPI was found within the large vesicles. Most of the VIPI terminals were ensheathed by the cytoplasm of the Schwann cells together with CA terminals, identified as those with a number of small granulated vesicles. In some cases, they were directly apposed to the smooth muscle cells at a distance of about 100 nm. SPI terminals were frequently solitary but about 30% were located together with CA and other (neither SPI nor CA) terminals ensheathed by Schwann cells, directly apposed to the smooth muscle cells at a distance of about 100 nm. On the other hand, NPYI terminals were also identified as CA terminals, indicating the coexistence of these two substances. These findings suggest a close interrelationship between peptidergic and CA nerve terminals in the neurogenic control of cerebral blood vessel function.
Assuntos
Artérias Cerebrais/inervação , Terminações Nervosas/ultraestrutura , Neurotransmissores/metabolismo , Animais , Técnicas Imunoenzimáticas , Masculino , Microscopia Eletrônica , Terminações Nervosas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuropeptídeo Y , Ratos , Substância P/metabolismo , Peptídeo Intestinal Vasoativo/metabolismoRESUMO
Recent experiments have shown that exogenous basic fibroblast growth factor (bFGF) enlarges fracture callus and accelerates the healing of osteotomized long bones. The actions of bFGF are mediated by four different transmembrane receptors (FGFR1-4). Among them, FGFR1 has a high affinity for bFGF, and gain-of-function mutations of the FGFR1 gene cause craniosynostosis in humans. Gene expression for FGFR1 has been analyzed in embryogenesis; however, in skeletal repair, detailed expression of FGFR1 has not been fully established. In the present study, a rat model of closed femoral fracture healing was used to quantify mRNA encoding the FGFR1 and to characterize cells expressing FGFR1 by in situ hybridization. Gene expression for FGFR1 was rapidly upregulated after fracture; its mRNA level on day 1 was 3.4-fold higher than that of unfractured femora. At this stage, a moderate signal for FGFR1 was detected in periosteal osteoprogenitor cells, inflammatory cells near fracture sites, and cells among muscle layers. FGFR1 mRNA reached peak expression when callus remodeling actively progressed (6.8-fold on day 14), and remained elevated even in the later stages of healing (6.3-fold on day 28). During the intermediate stage of fracture healing, a strong signal for FGFR1 was diffusely distributed in mature osteoblasts in the hard callus, and mature osteoclasts also expressed a weak signal for FGFR1. These results suggest that FGF/FGFR1 signaling has multifunctional roles during fracture healing and may regulate both osteoblasts and osteoclasts, contributing to bone formation and callus remodeling.
Assuntos
Consolidação da Fratura/fisiologia , Receptores Proteína Tirosina Quinases/genética , Receptores de Fatores de Crescimento de Fibroblastos/genética , Animais , Calo Ósseo/fisiopatologia , Fêmur/lesões , Fêmur/fisiologia , Fator 2 de Crescimento de Fibroblastos/genética , Expressão Gênica/fisiologia , Hibridização In Situ , Masculino , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos , Ribonucleases , Transdução de Sinais/fisiologiaRESUMO
The localization of glycine receptors was immunocytochemically examined in the rat brain using a monoclonal antibody against the affinity-purified glycine receptor. Glycine receptors were concentrated in the lower brainstem, whereas no immunoreactivity was observed in the diencephalon and forebrain except in a few diencephalic nuclei. The highest density of receptors was found in the cranial motor nuclei, reticular formation, parabrachial area, dorsal and ventral cochlear nuclei, and dorsal and ventral tegmental nuclei. Differences were observed in the distribution of immunoreactive elements in the various brain regions. In the cerebellar cortex, the immunoreactivity was exclusively seen along the dendrites of the Purkinje cells. On the other hand, glycine receptors were detected on the cellular membrane of the soma of the cochlear nuclei, trigeminal motor nucleus, parabrachial area, lateral reticular nucleus, dorsal nucleus of the lateral lemniscus, cerebellar nuclei, trigeminal spinal nucleus, anterior horn and reticular formation. In other regions, the receptors were evenly distributed throughout the neuropil.
Assuntos
Anticorpos Monoclonais , Química Encefálica , Receptores de Neurotransmissores/análise , Animais , Imuno-Histoquímica , Masculino , Ratos , Receptores de GlicinaRESUMO
The distribution of choline-acetyltransferase-like immunoreactive structures in the rat hypothalamus and preoptic area was examined by using avidin-biotin immunocytochemistry. We found that the hypothalamus is richly innervated by the cholinergic neuron system. Sites containing cholinergic neurons of varying density were: medial and lateral preoptic areas, septohypothalamic nucleus, median preoptic area, lateral hypothalamus including the perifornical area, anterior hypothalamic nucleus, arcuate nucleus, dorsomedial hypothalamic nucleus, posterior hypothalamic nucleus, dorsal and ventral premammillary nuclei, neuropil mediodorsal to the anterior hypothalamic nucleus, neuropil ventral to the anterior hypothalamic nucleus and ventromedial hypothalamic nucleus, neuropil between lateral hypothalamus and ventromedial hypothalamus, and neuropil between dorsal premammillary nucleus and posterior hypothalamic nucleus. There were also many varicose and non-varicose fibers in the preoptic area and hypothalamus. Two kinds of varicose fibers, one with strong immunoreactivity and the other with weak immunoreactivity, were seen. Non-varicose fibers were also detected in the optic chiasma and habenulo-interpeduncular tract. These fibers were passing fibers.
Assuntos
Colina O-Acetiltransferase/análise , Fibras Colinérgicas/citologia , Hipotálamo/anatomia & histologia , Animais , Carbazóis , Fibras Colinérgicas/enzimologia , Histocitoquímica , Hipotálamo/enzimologia , Técnicas Imunoenzimáticas , Masculino , Área Pré-Óptica/anatomia & histologia , Área Pré-Óptica/enzimologia , RatosRESUMO
In Drosophila, members of the leucine-rich repeat (LRR) family have significant functions in neural development. We have isolated mouse brain cDNAs which encode three new independent LRR proteins (neuronal leucine-rich repeat: NLRR-1, NLRR-2, NLRR-3). Levels of expression of these NLRR mRNAs were measured in a unilateral cortical injury model by in-situ hybridization and Northern blot analysis. In the injured cerebral cortex, only NLRR-3 mRNA increased in layers 2-3, while the other two genes showed no up-regulation. The level of NLRR-3 mRNA induction peaked around 7-10 days postinjury. This study suggests that NLRR-3 may be an important component of the pathophysiological response to brain injury.
Assuntos
Lesões Encefálicas/metabolismo , Encéfalo/metabolismo , Córtex Cerebral , Proteínas do Tecido Nervoso/biossíntese , Transcrição Gênica , Animais , Drosophila , Hibridização In Situ , Glicoproteínas de Membrana , Camundongos , Camundongos Endogâmicos ICR , Sondas RNA , RNA Mensageiro/biossíntese , Fatores de TempoRESUMO
We cloned genes the expression of which were induced 3 days after cortical injury of rat brain by a differential display technique, and four novel and known sequences were isolated. Among these sequences, the sgk gene which was recently identified as a novel member of the serine/threonine protein kinase gene family, was selected for analysis of its expression patterns in rat brain by northern blotting and in situ hybridization, because hybridization signals were strong at the lesion sites. Expression of sgk mRNA was induced within 3 days after injury, and was maintained at a high level for at least 14 days. The cells which strongly expressed the sgk gene were in the deep layers of the cortex and in the corpus callosum. In situ hybridization analysis for sgk and myelin proteolipid protein mRNA using serial sections showed that the distribution of both signals was very similar at the damaged regions. Therefore, it is likely that the sgk transcript is expressed by oligodendrocytes after brain injury. Investigation of the developmental expression of the sgk gene showed that neurons in layers I and II of the cortex, lateroposterior and laterodorsal thalamic nucleus, and ventral posterolateral and posteromedial thalamic nucleus strongly expressed sgk mRNA at postnatal day 1 and day 7, but these neurons showed no expression in fetal or adult brain. These results suggest that the induction of sgk gene may be associated with a series of axonal regenerations after brain injury, and in addition, the sgk gene may also play important roles in the development of particular groups of neurons in the postnatal brain.
Assuntos
Lesões Encefálicas/enzimologia , Encéfalo/enzimologia , Córtex Cerebral/enzimologia , Regulação Enzimológica da Expressão Gênica , Proteínas Nucleares , Proteínas Serina-Treonina Quinases/biossíntese , Envelhecimento/metabolismo , Animais , Animais Recém-Nascidos , Sequência de Bases , Northern Blotting , Encéfalo/crescimento & desenvolvimento , Clonagem Molecular , Corpo Estriado/enzimologia , Primers do DNA , Hipocampo/enzimologia , Proteínas Imediatamente Precoces , Imuno-Histoquímica , Hibridização In Situ , Masculino , Dados de Sequência Molecular , Regeneração Nervosa , Reação em Cadeia da Polimerase , Proteínas Serina-Treonina Quinases/análise , Proteínas Serina-Treonina Quinases/genética , Sondas RNA , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Ratos , Ratos Wistar , Tálamo/enzimologia , Transcrição GênicaRESUMO
Mouse P19 embryonal carcinoma cells can be reproducibly differentiated into neurons and glial cells upon treatment with high concentration of retinoic acid (RA). In order to understand the molecular mechanisms that control early neural differentiation, we screened a cDNA library made from 24-h RA-treated P19 cells with subtracted cDNA probes. One clone was positive in the secondary screening and was designated as p205. This clone (1.1 kb) has an open reading frame of 317 amino acids with homology to G-protein beta subunit. This protein sequence was identical to chicken and human genes previously identified as a major histocompatibility complex-associated gene. The complete conservation of its amino acid sequence between mouse, human and chicken provides strong evidence that the p205 protein fulfills a fundamental function. Developmental Northern blot analysis revealed that a p205 mRNA is expressed at high levels in the embryonic mouse brain, decreasing as development proceeds. In situ hybridization revealed that p205 mRNA is strongly and ubiquitously expressed in the embryonic and early postnatal mouse brain. This expression decreased during postnatal development and was localized in the dentate gyrus, habenula, piriform cortex, paraventricular nucleus of the hypothalamus and supraoptic nucleus of the adult brain. These results suggest that this protein plays an important role in the developing brain and neuronal differentiation.
Assuntos
Envelhecimento/metabolismo , Encéfalo/metabolismo , Carcinoma Embrionário/metabolismo , Neuropeptídeos/biossíntese , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Clonagem Molecular , Sondas de DNA , Desenvolvimento Embrionário e Fetal , Biblioteca Gênica , Idade Gestacional , Camundongos , Dados de Sequência Molecular , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neuropeptídeos/genética , Especificidade de Órgãos , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Receptores de Quinase C Ativada , Tretinoína/farmacologia , Células Tumorais CultivadasRESUMO
We studied the localization of Rlim-1 mRNAs, the rat Xlim-1 homolog, in the developing rat brain using in situ hybridization histochemistry. On embryonic day 13 (E13), strong signals were observed in the most superficial layer of the telencephalon, the zonalimitans intrathalamica, the ventral thalamus, some nuclei of the hypothalamus, the tectum, the cerebellum, the lower brainstem and the spinal cord. In the above-mentioned regions except the cerebellum, the distribution pattern remained almost the same from embryonic stage to adulthood but the intensity of expression gradually decreased after birth. In the cerebellum, the distribution pattern changed. during development; all the primordium of cerebellum in E13, the external granular and the Purkinje cell layers in postnatal day 7 (P7), and only the Purkinje cell layer in the adult expressed positive signals. These results suggest that Rlim-1 may be involved in region specification.
Assuntos
Encéfalo/metabolismo , Proteínas de Homeodomínio/genética , RNA Mensageiro/análise , Animais , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Cerebelo/metabolismo , Diencéfalo/metabolismo , Desenvolvimento Embrionário e Fetal/fisiologia , Idade Gestacional , Hibridização In Situ , Proteínas com Homeodomínio LIM , Mesencéfalo/metabolismo , Ratos , Ratos Wistar , Homologia de Sequência de Aminoácidos , Telencéfalo/metabolismo , Fatores de TranscriçãoRESUMO
We previously isolated two novel serine/threonine kinase genes containing the LIM motif (LIMK-1 and LIMK-2) from a rat cDNA library. To examine the functions of these genes, we performed in situ hybridization in the developing rat nervous system. LIMK-1 and LIMK-2 mRNAs mostly co-localized during development and are expressed preferentially in the central nervous system during mid-to-late gestation but the signals decreased during the post-natal period. However, differential gene expression was observed in some nuclei in the CNS; LIMK-1 mRNA was intensely expressed in the facial motor nucleus, the hypoglossal nucleus, deep nuclei of the cerebellum and the layers 3, 5 and 6 of the adult cerebral cortex while only LIMK-2 mRNA was preferentially expressed in the some parts of the epithelium. In the nasal cavity, LIMK-1 and LIMK-2 mRNAs were expressed complementarily. Our results suggest that LIMK-1 and LIMK-2 may have different functions in these regions during development.
Assuntos
Processamento Alternativo , Encéfalo/enzimologia , Proteínas de Ligação a DNA/biossíntese , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Quinases/biossíntese , Proteínas Serina-Treonina Quinases/biossíntese , Envelhecimento , Animais , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , DNA Complementar , Desenvolvimento Embrionário e Fetal , Regulação Enzimológica da Expressão Gênica , Biblioteca Gênica , Variação Genética , Rim/embriologia , Rim/enzimologia , Rim/crescimento & desenvolvimento , Quinases Lim , Neurônios/enzimologia , Especificidade de Órgãos , RNA Mensageiro/análise , Ratos , Transcrição Gênica , Dedos de ZincoRESUMO
In the course of studies to identify new members of the eph family of receptor tyrosine kinases, MDK1 and one of its splicing variants lacking a kinase domain, MDK1-T1, were identified. To gain insight into the functions of these subtypes, expression patterns of their mRNAs in the developing mouse nervous system were examined by Northern blotting and in situ hybridization histochemistry. Colocalization of their mRNAs was observed, but the levels of expression of each mRNA were developmentally regulated. These findings suggest functional differences between full-length and truncated forms of MDK1 receptor tyrosine kinase.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Família Multigênica , Sistema Nervoso/metabolismo , Splicing de RNA , Receptores Proteína Tirosina Quinases/genética , Animais , Desenvolvimento Embrionário e Fetal/fisiologia , Camundongos , Sistema Nervoso/embriologia , Sistema Nervoso/crescimento & desenvolvimentoRESUMO
To examine the roles of the eph subfamily of receptor tyrosine kinase (RTK), we isolated mouse cDNAs for sek, elk, and eck and localized their mRNAs in the developing mouse, with particular reference to the CNS development, by in situ hybridization. sek mRNA is most abundantly expressed throughout development; sek was detected in the germinal layer of the embryonic CNS during mid- to late-gestation and was widely expressed in the early postnatal brain. elk was expressed in the mantle layer of the embryonic CNS and showed a distribution complementary to that of sek. Differential expression of sek and elk was also observed in the early postnatal cerebellum; sek was expressed in the Purkinje cells, while elk was detected in the granule cells. eck was moderately expressed in the germinal layer of the embryonic CNS at mid-gestation, but its expression decreased as development proceeded. These spatio-temporally different patterns of gene expression suggest that these RTKs have distinct roles in mouse development despite their structural homology.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Família Multigênica , Sistema Nervoso/metabolismo , Receptores Proteína Tirosina Quinases/genética , Sequência de Aminoácidos , Animais , Northern Blotting , Clonagem Molecular , DNA Complementar/genética , Desenvolvimento Embrionário e Fetal/genética , Hibridização In Situ , Camundongos , Dados de Sequência Molecular , Sistema Nervoso/embriologia , Sistema Nervoso/crescimento & desenvolvimentoRESUMO
The fibroblast growth factor (FGF) receptor gene family now contains four members that encode homologous receptor-tyrosine kinases (RTKs) to each other. We have demonstrated that one of the members, FGFR-1 (also termed as flg), is expressed in the widespread but specific neuronal populations in the adult rat central nervous system (CNS). In the present study, we examined the expression pattern of another member, FGFR-2 (also termed as bek) and compared it with that of FGFR-1. In contrast with FGFR-1, we detected FGFR-2 expression primarily in the fiber tracts of the adult rat CNS, suggesting that the oligodendrocytes are the main sites of the FGFR-2 expression. These findings indicate that FGF may regulate neurons and glial cells through different subtypes of its cognate receptor.
Assuntos
Química Encefálica , Família Multigênica , Proteínas do Tecido Nervoso/biossíntese , Neurônios/metabolismo , Oligodendroglia/metabolismo , RNA Mensageiro/biossíntese , Receptores de Fatores de Crescimento de Fibroblastos/biossíntese , Animais , Sequência de Bases , Hibridização In Situ , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Sondas de Oligonucleotídeos , Ratos , Receptores de Fatores de Crescimento de Fibroblastos/genéticaRESUMO
Localization of mRNA for the c-kit receptor and its ligand (Sl factor) in the brain of adult rats was studied using in situ hybridization histochemistry. The mRNA for the c-kit receptor was detected in the forebrain, the lower brain stem and the cerebellum. In the forebrain, the c-kit mRNA signals were detected in the olfactory bulb, the caudate-putamen, throughout the superficial cortex, the accumbens nucleus, the nucleus of vertical limb diagonal band, the bed nucleus of anterior commissure, Ammon's horn, the entopeduncular nucleus, the subthalamic nucleus, the dorsal raphe nucleus, the parasubiculum, the presubiculum, the ventricular nucleus of lateral lemniscus, and the entorhinal cortex. In the lower brain stem, the signals were detected in the inferior colliculus, the spinal vestibular nucleus, the spinal tract nucleus of trigeminal nerve, and the pyramidal tract. In the cerebellum, the signals were detected in the molecular layer of the cortex and cerebellar nuclei. By contrast, the signals of mRNA for Sl factor were detected in the forebrain and the cerebellum. In the forebrain, the signals were detected in the olfactory bulb, the endopiriform nucleus, the septohippocampal nucleus, the habenular nuclei, and most of the thalamic nuclei. In the cerebellum, the signals were detected in Purkinje cells. Several pairs of structures were found in which mRNA of either the c-kit receptor or the Sl factor was expressed and between which the synaptic connection had been reported, suggesting that the interaction between the c-kit receptor and the Sl factor may play some roles in the development of such synaptic connections.
Assuntos
Encéfalo/anatomia & histologia , Proteínas Tirosina Quinases/genética , RNA Mensageiro/metabolismo , Animais , Química Encefálica , Tronco Encefálico/anatomia & histologia , Tronco Encefálico/metabolismo , Cerebelo/anatomia & histologia , Cerebelo/metabolismo , Digoxigenina , Feminino , Histocitoquímica , Hibridização In Situ , Ligantes , Bulbo Olfatório/anatomia & histologia , Bulbo Olfatório/metabolismo , Prosencéfalo/anatomia & histologia , Prosencéfalo/metabolismo , Sondas RNA , Ratos , Ratos WistarRESUMO
The Src-like protein-tyrosine kinases Fyn and Lyn are expressed in lymphocytes. Fyn is expressed in T cells at elevated levels and is associated with the T cell antigen receptor complex, whereas Lyn is expressed in B cells and is associated with membrane-bound immunoglobulin. Thus, these kinases are suggested to participate in antigen-mediated signal transduction in lymphocytes. Previous report showed that fyn was also expressed in brain, but its cellular distribution was not examined. Expression of Lyn in neural tissues was not previously reported. Here we report that both fyn and lyn are expressed in discrete regions of the brain. To throw light on their functions in the brain, we investigated their expressions during brain ontogenesis in mice. In situ hybridization analysis showed that Fyn mRNA was specifically expressed in neurons of embryos and newborn mice. In adult animals, fyn mRNA was expressed in oligodendrocytes as well as neurons. In contrast, the expression of lyn mRNA was relatively low in brains of embryos and newborn mice, but in adults the transcript was specifically expressed in the granular layer of the cerebellum. Therefore, the Fyn and Lyn kinases may regulate distinct functions of specific cells during brain development. The specific expressions of Fyn and Lyn in both lymphatic and neural tissues could suggest common signalling mechanisms in the immune system and central nervous system.
Assuntos
Encéfalo/enzimologia , Proteínas Tirosina Quinases/análise , Proteínas Proto-Oncogênicas/análise , Receptores de Antígenos de Linfócitos T/química , Transdução de Sinais/fisiologia , Quinases da Família src , Animais , Hibridização In Situ , Camundongos , Camundongos Endogâmicos , Especificidade de Órgãos/fisiologia , Proteínas Proto-Oncogênicas c-fynRESUMO
It is well established that leucine-rich repeat (LRR) proteins such as connectin, slit, chaoptin, and Toll have pivotal roles in neuronal development in Drosophila as cell adhesion molecules. However, to date, little information concerning mammalian LRR proteins has been reported. In the present study, we sought LRR proteins of the mouse brain, based on the assumption that fundamental mechanisms are conserved between different species. We screened a neonatal mouse brain cDNA library with a human partial cDNA encoding LRR protein as a probe. We obtained two independent cDNAs encoding LRR proteins, designated NLRR-1 and NLRR-2 (Neuronal Leucine-Rich Repeat proteins). We analyzed the whole sequence of NLRR-1 and partial sequence of NLRR-2. Sequence analysis showed that these two clones are about 60% homologous to each other, and that NLRR-1 protein is a transmembrane protein. Northern blot analysis and in situ hybridization histochemistry showed that both NLRR-1 and NLRR-2 mRNAs were expressed primarily in the central nervous system (CNS); NLRR-1 mRNA was also detected in the non-neuronal tissues such as cartilage, while NLRR-2 mRNA expression was confined to the CNS at all developmental stages. These results suggest that there is at least one LRR protein family in the mouse and that these molecules may play significant but distinct roles in neural development and in the adult nervous system.