Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interactions between neurofilament side arms may modulate axon caliber. To investigate this hypothesis, we derived transgenic mice expressing a fusion protein in which the carboxyl terminus of the high molecular weight neurofilament protein (NFH) was replaced by beta-galactosidase. The transgene, regulated by NFH sequences, was expressed in projection neurons. However, the fusion protein remained in perikarya precipitating large filamentous aggregates. Axons were not invested with neurofilaments and developed only small calibers. Perikaryal aggregates, with similar structural features, are associated with neurodegenerative diseases, but these mice showed few ill effects and their neurons rarely degenerated. We conclude that an organized neurofilament cytoskeleton is required by axons to achieve large calibers but is not essential for neuronal function or extended survival.
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PMID:Neurofilament-deficient axons and perikaryal aggregates in viable transgenic mice expressing a neurofilament-beta-galactosidase fusion protein. 811 Apr 65

An efficient gene trap strategy was devised for identifying the genes that are expressed in the mouse developing nervous system. Mouse embryonic stem (ES) cell lines that carried independent integrations of a gene trap vector, pSneolN/acZA, were allowed to differentiate in a suspension culture system. To select cells containing neurons, astrocytes or neuron-glia precursors, cell lines were immunohistochemically examined with antibodies against neuron-specific proteins (neurofilament protein 150 kD and microtubule associated protein 2), glial fibrillary acidic protein or nestin. Three cell clones (GT3-8, 11 and 12) were immunoreactive to either of the antibodies employed and at the same time positive for beta-galactosidase activity. When chimeric embryos were generated by the use of the above 3 cell lines, some cells in their nervous system showed X-gal staining. Thus the major advantage of the present gene trap method lies in its prescreening step of manipulated ES cells prior to generation of chimeric animals. This method holds promise as a useful tool for investigating the genes involved in the development of the nervous system.
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PMID:A gene trap strategy for identifying the gene expressed in the embryonic nervous system. 876 26

Mice lacking neurotrophin-3 (NT-3) have been shown previously to be born with severe sensory deficits. This study characterizes the developmental course of this deficit in the trigeminal sensory ganglion, which in NT-3 homozygous mutants contains only 35% of the normal number of neurons at birth. At embryonic day 10.5 (E10.5), normal numbers of neurons, as assessed by expression of neurofilament protein and of total cells, are present in the ganglia of mutant homozygotes. During the next 3 d (E10.5-E13.5), virtually all of the deficit develops, after which mutant animals retain only approximately 30% the normal number of neurons. Quantification of neuronal and neuronal precursor numbers in normal and mutant animals reveals that neurons are specifically depleted in the absence of NT-3. A deficiency in precursor proliferation is only seen after most of the neuronal deficit has developed. Numbers of apoptotic cells in the ganglia of mutant animals are elevated during this same interval, indicating that the neuronal deficit is caused, in large part, by increased cell death of embryonic neurons. To determine sources of NT-3 in the trigeminal system, we examined the expression pattern of beta-galactosidase in mice, in which lacZ has replaced the NT-3 coding exon. E10.5-E11.5 embryos exhibit intense reporter expression throughout the mesenchyme and epithelia of the first branchial arch. Beta-galactosidase expression in E13.5 embryos is largely confined to the oral epithelium and the mesenchyme underlying the skin. Throughout the E10.5-E13.5 interval, the trigeminal ganglion and its targets in the CNS do not express reporter activity. We conclude that NT-3 acts principally as a peripherally derived survival factor for early trigeminal neurons.
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PMID:Neurotrophin-3 is a survival factor in vivo for early mouse trigeminal neurons. 892 22

A non-replicating triple-mutant herpes simplex virus (14H delta 3vhsZ) expressing the bacterial marker enzyme beta-galactosidase, was assessed for neurotropism and cytopathic effects as a vector for gene transfer into differentiated phaeochromocytoma 12 cells in vitro and into spinal sympathetic neurons in vivo. In the in vivo study, the 14H delta 3vhsZ was injected into the adrenal gland of hamsters. For comparison, an evaluation of two adenovirus vectors, AdCA17lacZ and AdCA36lacZ, was performed. Infection of the differentiated phaeochromocytoma 12 cells by 14H delta 3vhsZ resulted in intense beta-galactosidase staining in 80-90% of the cells without changes in cell morphology, detected by light microscopy, after a period of four days. No cytoskeletal disruption was detected by immunocytochemistry for the neurofilament protein and no apoptosis was demonstrated by the Hoescht stain for nuclear chromatin in virus-infected cells in comparison to mock-infected control cells. Twoto three days after adrenal inoculation with 14H delta 3vhsZ, beta-galactosidase was detected in 240 preganglionic neurons per hamster (n = 8), a number equal to about 25% of the population of targeted neurons. The beta-galactosidase reaction product extended throughout the normal kite-shaped neuronal somata and extensive dendritic arbour. The number decreased to 120 by five days (n = 3) and to two by eight days (n = 4). This decrease was presumably due to loss of expression of the marker gene and not to cell death because, at eight days, the number of sympathetic pregnanglionic neurons in the nucleus intermediolateralis, pars principalis, that were immunoreactive for the neurotransmitter enzyme choline acetyltransferase, and demonstrated nicotinamide adenine dinucleotide phosphate-diaphorase activity, were the same on the infected left side of the cord as on the uninfected right side. Inflammatory cells surrounded some of the infected neurons at five days but by eight days the infiltrate was reduced. Infection of differentiated phaeochromocytoma 12 cells by AdCA17lacZ and AdCA36lacZ also resulted in marker gene expression in a large proportion of the cells (80-90%) in the absence of cytopathic effects. In contrast, four days after adrenal injection of AdCA17lacZ or AdCA36lacZ (n = 5 for each) only an average of three preganglionic neurons per hamster expressed beta-galactosidase activity, despite clear adrenal infection. AdCA17lacZ and AdCA36lacZ both produced light patches of staining confined to the neuronal soma. These neurons had normal morphology but sometimes were surrounded by an inflammatory infiltrate. In conclusion, the non-replicating herpes simplex virus, 14H delta 3vhsZ, had minimal cytotoxic effects in neurons, in vitro or in vivo, and was efficiently transported from the adrenal gland to infect many sympathoadrenal pregnanglionic neurons. In contrast, very few neurons demonstrated beta-galactosidase activity after injection into the adrenal gland of AdCA17lacZ and AdCA36lacZ. Therefore, 14H delta 3vhsZ is a more suitable vector than either of the adenovirus vectors tested for eliciting short-term changes in preganglionic neuron gene expression.
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PMID:Analysis of a multi-mutant herpes simplex virus type 1 for gene transfer into sympathetic preganglionic neurons and a comparison to adenovirus vectors. 969 36

Diabetic neuropathy is characterized by slowing of conduction velocity and axonal atrophy. Both of these cardinal features of neuropathy might be linked to impaired neurofilament investment of axons. Since neurofilaments form the critical structural latticework of axons, their importance in neuropathy is of interest. We tested directly the relationship of neurofilaments to diabetic neuropathy by superimposing streptozotocin-generated diabetes on a unique but viable transgenic mouse described by Eyer and Peterson. These mice express a fusion protein in which the carboxyl terminus of the high molecular weight neurofilament protein (Nf-H) was replaced by beta-galactosidase, in turn blocking normal neurofilament export and rendering axons completely lacking neurofilaments. Despite similar levels of hyperglycaemia, diabetic mice lacking neurofilaments developed progressive slowing of conduction velocity in their motor and sensory fibres between 4 and 8 weeks after the onset of diabetes (P < 0.05), unlike diabetic mice with normal neurofilaments, who developed only mild evidence of neuropathy over the same time-frame. Diabetic mice without neurofilaments, but not those with neurofilaments, had a progressive decline in the amplitude of the caudal nerve compound action potential and there were trends toward increased axonal atrophy in diabetics lacking neurofilaments. Single daily doses of insulin that restored normoglycaemia (0.1 IU subcutaneous insulin daily 5 of 7 days weekly for 4 weeks) reversed conduction slowing and restored sensory axon calibre. Our findings indicate that abnormalities in neurofilament export or transport alone cannot account for features of diabetic neuropathy. Instead, neurofilaments may allow axons to better resist the ravages of diabetes. Our findings also confirm the impact of insulin on reversing the phenotype.
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PMID:Accelerated diabetic neuropathy in axons without neurofilaments. 1528 71