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

We have analyzed the cis-regulatory elements in the 5' flanking region of the Drosophila choline acetyltransferase gene (ChAT, E.C.2.3.1.6). DNA fragments were fused to the Escherichia coli lacZ reporter gene and introduced into the Drosophila germ line by P-element-mediated transformation. A 7.4 kb 5' flanking sequence directed beta-galactosidase expression in the adult optic lobes and other well-defined CNS structures with a pattern very similar to the distribution of endogenous ChAT protein. In contrast, the proximal 3.3 kb and 1.2 kb of 5' flanking DNA directed lacZ expression in only selected subsets of the structures seen with the 7.4 kb lacZ construct. Our results indicate that both qualitative and quantitative regulatory elements are present in the 5' flanking DNA and that these elements distinguish various subsets of cholinergic neurons. We have also fused the same 5' flanking DNA sequences to wild-type ChAT cDNA and used these constructs to transform Chatsl mutant flies. Not only the 7.4 kb cDNA construct, but also the 3.3 and 1.2 kb constructs, rescued Chatsl from temperature-dependent paralysis and adult lethality, indicating that the regulatory information in any of these genomic fragments can drive sufficient wild-type ChAT expression to overcome these mutant phenotypes.
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PMID:Analysis of cis-regulatory elements in the 5' flanking region of the Drosophila melanogaster choline acetyltransferase gene. 137 60

Trophic factors may function as one of the epigenic signals responsible for the proliferation, growth, migration, and differentiation of neurons and glia during embryogenesis. The present study reports that basic fibroblast growth factor (bFGF) at high concentrations (10-100 ng/ml) is a mitogen for embryonic spinal cord cells that have already committed to a neuronal pathway and are expressing neuronal phenotypes (neuroblasts). Neuroblasts proliferate with a doubling time of 2.5 d. To characterize the nature of cells proliferating in response to bFGF, we have established long-term cultures of neuroblasts that can be passaged, freeze thawed, and recultured. In cultures the proportion of astrocytes remained the same, indicating limited survival and proliferation of these cells in response to bFGF. These results indicate that bFGF has mitogenic effects preferably on neuroblasts. The morphological and biochemical characterizations of the neuronal populations present in the long-term neuroblast cultures are presented here. The presence of cholinergic and GABAergic neurons in the cultures was established by immunocytochemical analysis. The cultures contain a small number of motoneurons as judged by their immunostaining with ChAT, low-affinity NGF receptor (LNGFR), and large size. Among all other growth factors tested for their mitogenic effects on embryonic spinal cord cells in culture, only epidermal growth factor (EGF) showed such effects, but to a lesser degree. The proliferative nature of neuroblasts has made it possible to transduce the Escherichia coli beta-galactosidase (LacZ) gene stably into these cells in vitro using a retroviral vector. The transfected cells expressing the foreign gene can be passaged, freeze thawed, and recultured without the loss of transgenes. The ability to transduce foreign genes stably into these cells permits implantation of these cells in the spinal cord to study cellular and biochemical behaviors and gene expression in defined neuronal populations in in vivo environments.
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PMID:Spinal cord neuroblasts proliferate in response to basic fibroblast growth factor. 820 71

Transforming growth factor-alpha (TGF-alpha), a member of the epidermal growth factor (EGF) family, binds to the EGF-receptor (EGF-R). The early expression and widespread distribution of TGF-alpha and EGF-R in the developing central nervous system (CNS) suggest that TGF-alpha may play a role in the developing CNS. To study possible effects of TGF-alpha on cholinergic differentiation in the basal forebrain, we cultured septal nuclei with adjacent basal forebrain from embryonic rat brain in the presence and absence of TGF-alpha. At the highest dose of TGF-alpha used (100 ng/mL), activity of choline acetyltransferase (ChAT; EC 2.3.1.6) and the number of cholinergic neurons doubled. However, because protein levels tripled, specific ChAT activity actually declined. To determine the mechanism accounting for the increase in ChAT, we labeled dividing precursors present in the cultures with a replication-deficient retrovirus expressing beta-galactosidase in the presence and absence of TGF-alpha. By staining the cultures for both LacZ and ChAT, we determined that the precursor population expanded in size (individually labeled clones contained more cells), but the percentage of cholinergic neurons present in the clones was unchanged. Therefore, while TGF-alpha expands the precursor pool, it does not promote cholinergic differentiation. Interleukin-9, included to prompt neuronal differentiation, did not by itself increase ChAT activity, nor did it enhance the action of TGF-alpha. This was true even when basic fibroblast growth factor was included.
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PMID:Transforming growth factor-alpha expands progenitor cells of the basal forebrain, but does not promote cholinergic differentiation. 982 46

Neurodegenerative diseases represent promising targets for gene therapy approaches provided effective transfer vectors. In the present study, we evaluated the effectiveness of LacZ-expressing lentiviral vectors with two different internal promoters, the mouse phosphoglycerate kinase 1 (PGK) and cytomegalovirus (CMV), to infect striatal cells. The intrastriatal injection of lenti-beta-Gal vectors lead to 207, 400 +/- 11,500 and 303,100 +/- 4,300 infected cells in adult rats, respectively. Importantly, the beta-galactosidase activity was higher in striatal extracts from PGK-LacZ-injected animals as compared to CMV-LacZ animals. The efficacy of the system was further examined with a potential therapeutic gene for the treatment of Huntington's disease, the human ciliary neurotrophic factor (CNTF). PGK-LacZ- or PGK-CNTF-expressing viruses were stereotaxically injected into the striatum of rats, 3 weeks later the animals were unilaterally lesioned with 180 nmol of quinolinic acid (QA). Control animals displayed 148 +/- 43 apomorphine-induced rotations ipsilateral to the lesion 5 days postlesion as compared to 26 +/- 22 turns/45 min in the CNTF-treated group. The extent of the striatal damage was significantly diminished in the CNTF-treated rats as indicated by the 52 +/- 9.7% decrease of the lesion volume and the sparing of DARPP-32, ChAT and NADPH-d neuronal populations. These results further establish that lentiviruses may represent an efficient gene delivery system for the screening of therapeutic molecules in Huntington's disease.
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PMID:Neuroprotective effect of a CNTF-expressing lentiviral vector in the quinolinic acid rat model of Huntington's disease. 1144 52