摘要:

AbstractFragments of striatum or cerebellum from E 25 rabbit embryo were implanted into either the striatum or the mesencephalon of newborn mice. Implanted rabbit astrocytes were selectively identified by mono‐donal antibodies to the GFAP which are unable to combine with mouse GFAP. Previous investigations had shown that xenogenic astrocytes have the capacto migrate in host CNS. The purpose of this study was to compare the patterns of migration of transplant‐derived astroglial cells according to the topographic origin of the transplant and location of the grafting site. We found that the migration pattern of the grafted cells from any of both selected sites of implantation was independent from the topographic origin of the transplant. The routes as well as the distances of migration were similar after homo‐ or heterotopic transplantation. We conclude that astroglial cells or their precursors do not express information which would direct them to move specifically toward a defined region in the host brain according to the region of origin in the

ISSN:0360-4012    

DOI:10.1002/jnr.490290402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractMyelin‐associated glycoprotein (MAG) is a cell surface molecule expressed by oligodendrocytes and Schwann cells. In order to determine whether MAG expression can confer adhesive properties to cells which normally do not aggregate in suspension, the cDNA encoding the long form of MAG (L‐MAG) was introduced into L cell fibroblasts by retroviral infection. Clonal L cell lines expressing MAG were then subjected to a cell aggregation assay. Our results indicate that L‐MAG can function as an intercellular adhesion molecule in a heterologous cell system. A critical threshold value of L‐MAG expression was required for cell aggregation to occur. The adhesive properties of these cells were specific to MAG, since monoclonal antibodies directed against its extracellular domain inhibited aggregation. Furthermore, the adhesion was found to be calcium‐ and temperature‐independent. Cell sorting experiments demonstrated that L‐MAG‐expressing cells bind in a heterotypic fashion to parental L cell fibroblasts. These results suggest that L‐MAG can function as a heterotypic cell adhesion molecule recognizing a cell surface mole‐cule(s) e

ISSN:0360-4012    

DOI:10.1002/jnr.490290403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractMammalian peripheral nerve fibres can regenerate after injury. In an attempt toward a better understanding of the underlying molecular events, we have isolated novel and known rat cDNA sequences, the expression of which are regulated during sciatic nerve regeneration. For this purpose, cDNA libraries were constructed from either the nerve segment distal to the crush site or the corresponding contralateral uninjured nerve of the same animals. These libraries were screened by differential hybridization and several transcriptionally repressed and induced sequences were isolated. Out of 2,000 cDNA clones screened from the distal library, 11 sequences were found to be induced in the distal nerve segment. This set of induced cDNAs included the rat homolog of vimentin, 28 S and 18 S ribosomal RNA species, and two novel sequences. Of 5,000 screened colonies of the contralateral library, 30 colonies contained sequences that were repressed in the distal segment after nerve crush. They were identified as myelin basic protein, myelin P0, α‐globin, cytochrome oxidase subunit 1, creatine kinase (muscle type, M) and collagen type I. In addition, five novel sequences were found that were dramatically repressed after sciatic nerve crush. Representative clones were tested by northern blot analysis to study their time course of transcriptional regulation during nerve regeneration. The observed patterns suggest that the regeneration phenomenon shows complex gene regulation in which the nonneuronal cells of the distal segment play an important role. Further characterization of the isolated regulated known and unknown sequences will increase our understanding of the molecular events associated with neuronal regenerati

ISSN:0360-4012    

DOI:10.1002/jnr.490290404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe gene encoding growth‐associated protein 43(Gap43), a neuronal phosphoprotein associated with axonal outgrowth and synaptic plasticity, is located on mouse chromosome 16 (MMU16). We examined the developmental expression of Gap43 in normal, trisomy 16 (Tsl6), and trisomy 19 (Tsl9) mouse brain using northern blot analysis and in situ hybridization as a first step toward understanding the neurobio‐logic consequences of increased gene dosage on brain development. Gap43 expression was detected by in situ hybridization throughout the mesencephalon, rhombencephalon, spinal cord, and first branchial arch in whole embryos as early as (Jay 10 of gestation (E10). By E15,Gap43expression was localized to cells in the retina, the olfactory bulbs, and anterior olfactory structures, the cortical plate, the basal telen‐cephalon, diencephalon, midbrain, hindbrain, ana spinal cord. Northern blot analysis detected a threefold increase inGap43mRNA levels in the brains of normal mice between E12–E18. At E15,Gap43mRNA levels were increased 35–40% in Tsl6 mouse brain and decreased 10% in Tsl9 mouse brain, relative to euploid littermate controls. Using in situ hybridization we found that overexpression ofGap43occurred in the diencephalon, medial and lateral basal telencephalon, and cortical plate region in Tsl6 mice relative to littermate controls. Thus, the degree of overexpression ofGap43mRNA in Ts16 mice is consistent with that expected from gene dosag

ISSN:0360-4012    

DOI:10.1002/jnr.490290405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe neuronal specific protein NP185, found associated with brain clathrin‐coated vesicles, formed a complex with unphosphorylated, but not with phos‐phorylated, clathrin light chains. The NP185–clathrin light chain complex was associated with casein kinase II activity, which, in the presence of polylysine, phosphorylated clathrin light chain b but not the NP185. The dissociation of this complex with 50% ethylene glycol pH 11.5 suggests that NP185binds to hydrophobic domains of clathrin light chains. When NP185 molecules were retained by monoclonal antibody‐linked Sepharose beads, they bound synaptic vesicles, decoated vesicles and synaptosomal plasma membrane. Immunohistochemistry on mouse cerebellar tissue sections using 8G8, a monoclonal antibody raised against NP185, showed neuronal specific labeling closely following synaptic distribution. In immunoblots, NP185 shares similar epitopes to those detected in another assembly polypeptide, AP‐180, an indication that both proteins are identical. It appears that NP185 plays a specific role in nerve ending functions through its ability to induce clathrin to polymerize into cages, its interaction with synaptic vesicles, with the plasma membrane and with clathrin coat c

ISSN:0360-4012    

DOI:10.1002/jnr.490290406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe neural retina N‐acetylgalactosaminylphospho‐transferase (GalNAcPTase) is a cell surface molecule (Balsamo and Lilien, 1980, 1983; Balsamo et al., 1986a) that is tightly associated with, and glycosy‐lates, the calcium‐dependent, cell‐cell adhesion molecule, N‐cadherin (Balsamo and Lilien, 1990). N‐cad‐herin has been implicated in neuronal attachment and neurite outgrowth when at the surface of cels (Bixby et al., 1987, 1988; Matsunaga et al., 1988; Neugebauer et al., 1988; Tomaselli et al., 1988). The intimate association of the GalNAcPTase and N‐cadherin prompted us to test the possibility that the GalNAcPTase is also involved in the process of neurite outgrowth. We tested the effect of one polyclonal and two monoclonal anti‐GalNAcPTase antibodies in cultures of chick neural retina cells extending neurites on substrates requiring N‐cadherin, beta inte‐grin receptors, or the chicken homologue of L1, G4. The length and number of neurites produced were dramatically reduced on all of these substrates by the polyclonal and one of the monoclonal anti‐GalNAcPTase antibodies. The second monoclonal antibody bound to the cell surface but was not inhibitory, indicating that it reacts with a different epitope. The mechanism through which the retina cell surface GalNAcPTase may modulate neurite outgrowth on man

ISSN:0360-4012    

DOI:10.1002/jnr.490290407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractOligodendrocytes (OL) isolated from adult pig brains regenerate their processes and form a network of fibers after 14–18 days in vitro (DIV). Stimulation of protein kinase C (Pk‐C) by tumour promoters such as 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) produces at day 7 in vitro a similar network after only 20 hr. H‐7, an inhibitor of Pk‐C, as well as amiloride, which inhibits the subsequent Na+/H+exchange, reversibly suppress this effect. Activation of the protein kinase A or calmodulin pathway do not result in an increased OL process production. Furthermore, TPA induced proliferation in a subpopulation of OL. We conclude that the stimulation of Pk‐C is of utmost importance fo

ISSN:0360-4012    

DOI:10.1002/jnr.490290408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractPrevious studies from our laboratory suggest that Alzheimer'disease sera contain a repertoire of antibodies to the heavy neurofilament subunit (NF‐H) and that a subpopulation of these antibodies bind specifically to epitopes highly enriched in NF‐H isolated from the purely cholinergic electromotor neurons ofTorpedo. In the present study, we prepared and characterized monoclonal antibodies (MAbs) that bind to epitopes specifically enriched inTorpedocholinergic neurons. This was performed by a differential enzyme‐linked immunosorbent assay (ELISA) in which MAbs were selected that bind to epitopes much more abundant in the NF‐H protein ofTorpedocholinergic neurons than in NF‐H from the chemically heterogeneous Torpedo spinal cord. This yielded four MAbs, three of which (TC4, TC8, and TC21) were found to be specific to NF‐H and one (TC15) that reacts with both NF‐H and the medium‐size neurofilament sub‐unit NF‐M. Dephosphorylation abolishes the binding of MAbs TC4 and TC15 to Torpedo cholinergic NF‐H, partially reduces that of MAb TC21 and has no effect on the binding of MAb TC8. This suggests that the antigenic sites specific toTorpedocholinergic NF‐H contain phosphoryiated as well as non phosphory‐lated epitopes. All the MAbs cross

ISSN:0360-4012    

DOI:10.1002/jnr.490290409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA primary culture system of nearly pure neuronal cells from 14‐day‐old fetal rat spinal cord has been developed by combining a preplating step, the use of a chemically defined serum‐free medium, and bo‐rated polylysine‐coated dishes that prevented the formation of cell aggregates. About 98% of the cells were found to be immunostained with neuron‐specific enolase antibodies, confirming their neuronal nature. The cultures are composed essentially of a population of non‐motoneurons and contain few motoneurons, characterized by their large size and multipolar aspect, the presence of acetylcholinesterase (AChE), and the intense immunoreaction for growth‐associated protein GAP‐43. Neuronal precursor cells are also present in these cultures and proliferate during the first 3 days. The addition of bovine brain basic fibroblast growth factor (bFGF) stimulates their proliferation over a period of 2 days, as determined, by measurement of [125I]iododeoxyuridine incorporation and by immunocytochemical reaction after bro‐modeoxyuridine incorporation into nuclei. The proliferating cells were characterized as neurons by immunostaining against neuron‐specific enolase. Re‐combinant human bFGF and bovine brain acidic FGF (aFGF) exerted similar effects. Other growth factors, including epidermal growth factor (EGF), transforming growth factor β1 (TFG‐β1), and thrombin, were without effect on the proliferative activity of these neuronal cells. bFGF has no effect on the survival of motoneurons and on the fiber outgrowth of the whole neuronal population. However, bFGF affects the development of bipolar AChE‐pos‐itive neurons, probably belonging to the non‐motoneuron population. The data indicate that bFGF and aFGF are mitogens for neuroblasts from rat spinal cord in culture and that bFGF influences the development of a subpopulation of spin

ISSN:0360-4012    

DOI:10.1002/jnr.490290410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractRecent evidence indicates that the cerebellum has a dopaminergic system. In order to elucidate further the dopaminergic system in the cerebellum, we investigated the transport of dopamine (DA) in synaptosomal preparations of normal and reeler mice. For comparative purposes we also studied DA transport in synaptosomal preparations from striatum and frontal cortex and compared DA transport to nor‐adrenaline (NA) transport.[3H]‐DA transport into cerebellar synaptosomes was found to be a Na+‐dependent, two component system–a high affinity, low capacity and a low affinity, high capacity. In striatum [33H]‐DA is transported by a similar high but different low affinity component. Maximal velocities of both transport components in the striatum were higher than the corresponding ones in the cerebellum. In the frontal cortex we also observed two [3H]‐DA transport components with affinities significantly lower than those in cerebellum and striatum.[3H]‐NA transport into synaptosomes, prepared from the three brain regions studied, showed two transport components with similar Kt and Vmax values, except for the high affinity component in striatum whose affinity is lower.In reeler mice [3H]‐DA transport was different from normal only in the cerebellum where the maximal velocity for both transport components was significantly higher (2 x). In contrast, no significant difference was observed in the transport of [3H]‐NA.The accumulated [3H]‐DA from cerebellar slices was found to be releasable by K+stimulation, in a Ca++‐dependent manner, and most of the released radioactivity was in the form of [3H]‐DA.These results indicate that in the cerebellum there is a low‐density dopaminergic system which is distinct from the correspon

ISSN:0360-4012    

DOI:10.1002/jnr.490290411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY