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1.
A protein induced during nerve growth (GAP-43) is a major component of growth-cone membranes 总被引：24，自引：0，他引：24
J H Skene R D Jacobson G J Snipes C B McGuire J J Norden J A Freeman 《Science (New York, N.Y.)》1986,233(4765):783-786
Growth cones are specialized structures that form the distal tips of growing axons. During both normal development of the nervous system and regeneration of injured nerves, growth cones are essential for elongation and guidance of growing axons. Developmental and regenerative axon growth is frequently accompanied by elevated synthesis of a protein designated GAP-43. GAP-43 has now been found to be a major component of growth-cone membranes in developing rat brains. Relative to total protein, GAP-43 is approximately 12 times as abundant in growth-cone membranes as in synaptic membranes from adult brains. Immunohistochemical localization of GAP-43 in frozen sections of developing brain indicates that the protein is specifically associated with neuropil areas containing growth cones and immature synaptic terminals. The results support the proposal that GAP-43 plays a role in axon growth. 相似文献
2.
The neuronal growth-associated protein GAP-43 induces filopodia in non-neuronal cells 总被引：17，自引：0，他引：17
The neuron-specific protein GAP-43 is associated with the membrane of the nerve growth cone and thus may be important to the activity of this distinctive neuronal structure. Transient transfection of COS and NIH 3T3 cells with appropriate vectors resulted in expression of GAP-43 in these non-neuronal cells; as in neurons, transfected GAP-43 associated with the membrane. In addition, many long fine filopodial processes extended from the periphery of such transfected cells. Stable CHO cell lines expressing GAP-43 also exhibited processes that were more numerous, far longer, and more complex than those of CHO cell lines not transfected or transfected with control plasmids. Thus GAP-43 may directly contribute to growth cone activity by regulating cell membrane structure and enhancing extension of filopodial processes. 相似文献
3.
Electrical activity may regulate a number of neuronal functions in addition to its role in transmitting signals along nerve cells. The hypothesis that electrical activity affects neurite elongation in sprouting neurons was tested by stimulating individual snail neurons isolated in cell culture. The findings demonstrated that growth cone advance, and thus neurite elongation, is reversibly stopped during periods when action potentials are experimentally evoked. A decrease in filopodial number and growth cone area was also observed. Thus, action potentials can mediate the cessation of neurite outgrowth and thereby may influence structure and connectivity within the nervous system. 相似文献
4.
The anaphase-promoting complex (APC) is highly expressed in postmitotic neurons, but its function in the nervous system was previously unknown. We report that the inhibition of Cdh1-APC in primary neurons specifically enhanced axonal growth. Cdh1 knockdown in cerebellar slice overlay assays and in the developing rat cerebellum in vivo revealed cell-autonomous abnormalities in layer-specific growth of granule neuron axons and parallel fiber patterning. Cdh1 RNA interference in neurons was also found to override the inhibitory influence of myelin on axonal growth. Thus, Cdh1-APC appears to play a role in regulating axonal growth and patterning in the developing brain that may also limit the growth of injured axons in the adult brain. 相似文献
5.
【目的】 全面了解鸡下丘脑高丰度miR-101的组织表达情况和潜在生物学功能,为揭示下丘脑调控鸡机体能量平衡的分子机制奠定基础。【方法】 采用茎-环定量RT-PCR方法检测miR-101在固始鸡4个发育阶段、13种组织中的表达,利用Pictar算法预测miR-101的靶基因并对预测靶基因分别进行Gene Ontology分析、通路分析和分层富集。【结果】 miR-101的表达具有明显的时序特征和组织特异性,胚胎期各组织中的表达水平明显高于出壳后,脑部各组织中的表达水平明显高于其它被检测的组织,并在14胚龄下丘脑以及17胚龄小肠和腿肌中高丰度富集;miR-101的预测靶基因在生物学调节、代谢过程、发育过程和细胞过程等基本生物学过程中显著富集;针对神经系统发育的生物信息学分析显示,miR-101调控功能主要涉及脑发育、神经元分化、神经发生调节、神经胶质细胞分化和星形胶质细胞分化等生物学过程。【结论】 miR-101为脑部组织高丰度表达miRNA,在脑发育相关的许多生物学过程中可能发挥重要的调节作用。 相似文献
6.
Trophic stimulation of cultured neurons from neonatal rat brain by epidermal growth factor 总被引：17，自引：0，他引：17
Epidermal growth factor (EGF) is a potent polypeptide mitogen originally isolated from the adult male mouse submaxillary gland. It also acts as a gastrointestinal hormone. EGF-immunoreactive material has recently been identified within neuronal fibers and terminals in rodent brain. In the present study, EGF was found to enhance survival and process outgrowth of primary cultures of subneocortical telencephalic neurons of neonatal rat brain in a dose-dependent manner. This effect was observed with EGF concentrations as low as 100 picograms per milliliter (0.016 nanomolar) and was dependent on the continuous presence of EGF in the medium. Similar effects were observed with basic fibroblast growth factor, but several other growth-promoting substances, including other mitogens for glial elements, were without effect. Thus EGF, in addition to its mitogenic and hormonal activities, may act as a neurite elongation and maintenance factor for select neurons of the rodent central nervous system. 相似文献
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8.
Sreedharan J Blair IP Tripathi VB Hu X Vance C Rogelj B Ackerley S Durnall JC Williams KL Buratti E Baralle F de Belleroche J Mitchell JD Leigh PN Al-Chalabi A Miller CC Nicholson G Shaw CE 《Science (New York, N.Y.)》2008,319(5870):1668-1672
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder characterized pathologically by ubiquitinated TAR DNA binding protein (TDP-43) inclusions. The function of TDP-43 in the nervous system is uncertain, and a mechanistic role in neurodegeneration remains speculative. We identified neighboring mutations in a highly conserved region of TARDBP in sporadic and familial ALS cases. TARDBPM337V segregated with disease within one kindred and a genome-wide scan confirmed that linkage was restricted to chromosome 1p36, which contains the TARDBP locus. Mutant forms of TDP-43 fragmented in vitro more readily than wild type and, in vivo, caused neural apoptosis and developmental delay in the chick embryo. Our evidence suggests a pathophysiological link between TDP-43 and ALS. 相似文献
9.
应用免疫组织化学技术显示蛋鸡生长发育过程中下丘脑中生长抑素（ＳＳ）免疫阳性神经原的分布。发现蛋鸡在生长早期（１周龄和３周龄）ＳＳ神经原数量较多，６周龄时暂时降低，到９周龄又回升；在生长晚期（６１周龄）呈显著下降趋势。尽管公鸡和母鸡ＳＳ神经原数量没有显著差异，但母鸡的ＳＳ神经原数量从第３周到第６周明显下降，第９周时显著上升，表明ＳＳ神经原的发育具有性别差异。研究结果表明，蛋鸡下丘脑中ＳＳ神经原数量与血浆中ＧＨ水平呈负相关，下丘脑中ＳＳ控制着脑垂体中ＧＨ的分泌。 相似文献
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11.
A Mab to a unique cerebellar neuron generated by immunosuppression and rapid immunization 总被引：8，自引：0，他引：8
S Hockfield 《Science (New York, N.Y.)》1987,237(4810):67-70
The cerebellar cortex is perhaps the best characterized structure in the mammalian central nervous system. Although the major cerebellar cell classes are well known, a new class of cerebellar cortical neuron has now been identified with a monoclonal antibody (Mab) generated by a procedure for rapid immunization and selective immunosuppression of antibody responses. This procedure generates a high frequency of immunoglobulin G-class antibodies of desired specificity, and has allowed the generation of two antibodies that recognize subsets of cerebellar cortical neurons. One of these antibodies defines a previously unrecognized class of cerebellar neuron. The distribution and antigenic characteristics of this neuron suggest that it has a distinct role in cerebellar circuitry. 相似文献
12.
Biochemistry of information storage in the nervous system 总被引：11，自引：0，他引：11
I B Black J E Adler C F Dreyfus W F Friedman E F LaGamma A H Roach 《Science (New York, N.Y.)》1987,236(4806):1263-1268
The use of molecular biological approaches has defined new mechanisms that store information in the mammalian nervous system. Environmental stimuli alter steady-state levels of messenger RNA species encoding neurotransmitters, thereby altering synaptic, neuronal, and network function over time. External or internal stimuli alter impulse activity, which alters membrane depolarization and selectively changes the expression of specific transmitter genes. These processes occur in diverse peripheral and central neurons, suggesting that information storage is widespread in the neuraxis. The temporal profile of any particular molecular mnemonic process is determined by specific kinetics of turnover and by the geometry of the neuron resulting in axonal transport of molecules to different synaptic arrays at different times. Generally, transmitters, the agents of millisecond-to-millisecond communication, are subject to relatively long-lasting changes in expression, ensuring that ongoing physiological function is translated into information storage. 相似文献
13.
The role of localized instability of the actin network in specifying axonal fate was examined with the use of rat hippocampal neurons in culture. During normal neuronal development, actin dynamics and instability polarized to a single growth cone before axon formation. Consistently, global application of actin-depolymerizing drugs and of the Rho-signaling inactivator toxin B to nonpolarized cells produced neurons with multiple axons. Moreover, disruption of the actin network in one individual growth cone induced its neurite to become the axon. Thus, local instability of the actin network restricted to a single growth cone is a physiological signal specifying neuronal polarization. 相似文献
14.
K D Roeder 《Science (New York, N.Y.)》1966,154(756):1515-1521
Insect-eating bats find their aerial food by sonar, through emitting ultrasonic chirps and locating sources of echoes. Certain moths have ears sensitive to these chirps and can detect bats well beyond the range of the bats' sonar. On hearing a distant bat, many moths turn and fly directly away from the source of ultrasound. Only one sense cell in each ear of a moth provides the primary nervous information for this response. This article describes my initial attempts to find out how a moth's central nervous system processes the train of chirps reaching its two ears. The ear of a restrained moth is exposed to a sequence of artifically generated ultrasonic pulses that approximates the cries made by a bat. This stimulus can be varied with respect to ultrasonic frequency (pitch), pulse intensity, pulse duration, the interval between pulses, and pulse-train duration. The more sensitive acoustic sense cell responds to all frequencies between about 15,000 and 80,000 cycles per second, but the signal that it transmits to the moth's central nervous system contains no measure of frequency within this range. However, this nerve signal reports variations in the other parameters of the stimulus. The acoustic fiber connects, in the central nervous system, with various nerve cells that transform the signal farther. The signal from a pulse-marker neuron contains no measures of pulse intensity or pulse duration, reporting only changes in interpulse interval and pulse-train duration. A train-marker neuron reports only the duration of the pulse train. The stimulus parameters may be likened to keys, each of which is necessary to gain admittance through a given door but becomes superfluous once this door has been passed. This analogy suggests one of the ways in which a signal is transformed in its passage through the nervous system, and how its specificity is assured in eliciting a given response. In addition to undergoing this kind of transformation, neural signals generated in the two directionally sensitive ears must be combined if a flying moth is to steer a course away from a distant bat. Neurons have been discovered in the central ganglia which summate signals from the right and left ears. Other neurons are inhibited in their activity by stimulation of one ear. The moth may combine signals from these neurons with motor-nerve information on the attitude of its own wings, which act as oscillating baffles modifying its directional acoustic sensitivity 20 to 40 times a second as it flaps an erratic path through the darkness. 相似文献
15.
Huang JK Phillips GR Roth AD Pedraza L Shan W Belkaid W Mi S Fex-Svenningsen A Florens L Yates JR Colman DR 《Science (New York, N.Y.)》2005,310(5755):1813-1817
Nodes of Ranvier are regularly placed, nonmyelinated axon segments along myelinated nerves. Here we show that nodal membranes isolated from the central nervous system (CNS) of mammals restricted neurite outgrowth of cultured neurons. Proteomic analysis of these membranes revealed several inhibitors of neurite outgrowth, including the oligodendrocyte myelin glycoprotein (OMgp). In rat spinal cord, OMgp was not localized to compact myelin, as previously thought, but to oligodendroglia-like cells, whose processes converge to form a ring that completely encircles the nodes. In OMgp-null mice, CNS nodes were abnormally wide and collateral sprouting was observed. Nodal ensheathment in the CNS may stabilize the node and prevent axonal sprouting. 相似文献
16.
MYCN是癌基因中的核蛋白类调控基因.在前期采用Illumina60kSNP芯片开展的胴体性状的全基因组关联(GWAS)研究中发现,MYCN基因与胸肌、腿肌重达显著相关.为进一步验证该基因在肌肉发育调控中的作用,采用Q-PCR技术,系统检测成肌细胞增殖分化期、胚胎发育后期和出生至98日龄肌肉组织中MYCN基因的mRNA表达量,并比较12个组织的特异性表达差异.结果表明,在鸡成肌细胞增殖、分化过程中,MYCN基因mRNA表达量在分化期显著高于增殖期(P＜0.01),并随诱导分化时间的延长表达量上升;在胚胎期14～21胚龄,mRNA表达量随胚龄的延长而持续上升,18至21胚龄变化显著(P＜0.01);在出生至98日龄生产发育阶段,在0～14日龄的表达量呈急剧下降趋势(P＜0.01),14日龄后变化不显著(P＜0.05).通过12个组织特异性表达分析,MYCN在胸肌、腿肌中的表达量仅次于大脑和下丘脑中枢神经系统中的表达水平.综合各发育阶段的结果表明,MYCN基因参与了肌肉组织发育的调控,其功能主要作用在鸡胚胎发育后期至出生后14日龄之内.该研究为阐明鸡肌肉生长发育的遗传机制提供了理论依据. 相似文献
17.
鸡法氏囊中血管活性肠肽的表达特点 总被引：2，自引：1，他引：2
运用免疫组织化学超敏SP法对鸡不同生长阶段法氏囊中血管活性肠肽(VasoactiveIntestinal Peptide,VIP)的表达特点进行了研究。结果显示,法氏囊中VIP的表达范围广泛,涉及黏膜、黏膜下层和肌层,尤以黏膜上皮细胞和法氏囊小结髓质的表达为典型;随着日龄增加,黏膜上皮细胞VIP表达逐渐减弱,囊小结髓质一直保持较强的VIP阳性着色,囊小结皮髓质交界处上皮细胞层内VIP强阳性细胞有逐渐增多的趋势。鸡法氏囊中VIP阳性反应物质的广泛分布,提示法氏囊是神经系统以外产生VIP的又一个重要部位,法氏囊中的VIP可参与鸡免疫器官的功能调节,可作为一种信号分子介导神经内分泌系统和免疫系统间的相互作用。 相似文献
18.
The function of the neurite growth-promoting antigen INO has been tested in an in vivo neurite regeneration system, the rat iris. The sympathetic innervation of the irides was removed by a single systemic injection of 6-hydroxydopamine. The subsequent regeneration of sympathetic axons into the iris of one eye bathed by the INO antibody, which inhibits neurite growth in vitro, was compared with the regrowth of sympathetic axons into the iris of the animal's other eye, which contained control antibody. Antibodies were released within the eye by implanted hybridoma cells. Neurite regeneration was measured by assaying [3H]norepinephrine uptake into freshly explained irides. The blockage of the function of the INO antigen by the antibody resulted in a decreased rate of axonal regeneration, thus suggesting the involvement of the INO antigen in the process of neurite regeneration in vivo. 相似文献
19.
Neurons with oscillatory properties are a common feature of the nervous system, but little is known about how neural oscillators shape the behavior of neuronal networks or how network interactions influence the properties of neural oscillators. Mathematical models are used to examine the effect of electrically coupling an oscillatory neuron to a second neuron that is either silent or tonically firing. Models of oscillatory neurons with varying degrees of complexity show that this coupling can either increase or decrease the frequency of an oscillator, depending on its membrane potential wave form, the state of the neuron to which it is coupled, and the strength of the coupling. Thus, electrical coupling provides a flexible mechanism for modifying the behavior of an oscillatory neural network. 相似文献
20.
Nerve growth factor(NGF) binds to TrkA and forms a NGF/TrkA complex at the cell surface,which is then internalized into signaling endosomes and promotes neuronal survival and neurite outgrowth.The small GTPase Rab5 is reported to localize on the plasma membrane and early endosomes,regulating endosome fusion.It was reported that endogenous Rab5 function may need to be suppressed during NGF-induced neurite outgrowth and cell differentiation.Two Rab5 homologs(MoRab5A:MGG_06241 and MoRab5B:MGG_01185) were characterized from the rice blast fungus Magnaporthe oryzae,and MoRab5 B was identified as the Rab5 ortholog promoting early endosomal fusion,while MoRab5 A specialized to perform a non-redundant function in endosomal sorting.In this study,we examined whether MoRab5 A and MoRab5 B play different roles in NGF-induced neurite outgrowth and cell differentiation in PC12 cells(a rat pheochromocytoma cell line).Our data showed that MoRab5 B is a negative regulator of NGF signaling and neurite outgrowth in PC12 cells,similar to human Rab5(hRab5).MoRab5B:WT inhibits NGF signaling-dependent neurite outgrowth while the dominant-negative MoRab5 B mutant(MoRab5B:DN) enhances NGF signaling and neurite outgrowth.In contrast,MoRab5A:WT and MoRab5A:DN both significantly promote NGF-induced neurite outgrowth,indicating that MoRab5 B is more similar to hRab5 than MoRab5 A in the regulation of NGF signal transduction. 相似文献