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)

Potential labels for identifying embryonic raphe neurons and a clonal, neuronally differentiating, raphe-derived cell line, RN33B, in CNS transplantation studies were tested by first characterizing the labels in vitro. The labels that were tested included 4',6-diamidino-2-phenylindole hydrochloride, 1,1'-dioctadecyl-3,3,3'-tetramethylindocarbocyanine perchlorate, the Escherichia coli lacZ gene, Fast Blue, Fluoro-Gold, fluorescein-conjugated latex microspheres, fluorescein isothiocyanate-conjugated or nonconjugated Phaseolus vulgaris leucoagglutinin, methyl o-(6-amino-3'-imino-3H-xanthen-9-yl) benzoate monohydrochloride, or tetanus toxin C fragment. Subsequently, the optimal in vitro labels for embryonic raphe neurons and for RN33B cells were characterized in vivo after CNS transplantation. In vitro, 1,1'-dioctadecyl-3,3,3'-tetramethylindocarbocyanine perchlorate (DiI) optimally labeled embryonic neurons. The Escherichia coli lacZ gene optimally labeled RN33B cells. Most labels were rapidly diluted in cultures of embryonic astrocytes and proliferating RN33B cells. Some labels were toxic and were often retained in cellular debris. In vivo, DiI was visualized in transplanted, DiI-labeled raphe neurons, but not in astrocytes up to 1 mo posttransplant. DiI-labeled host cells were seen after transplantation of lysed, DiI-labeled cells. beta-Galactosidase was visualized in transplanted, Escherichia coli lacZ gene-labeled RN33B cells after 15 days in vivo. No beta-galactosidase was seen in host cells after transplantation of lysed, lacZ-labeled RN33B cells. The results demonstrate that labels for use in CNS transplantation studies should be optimized for the specific population of donor cells under study, with the initial step being characterization in vitro followed by in vivo analysis. Appropriate controls for false-positive labeling of host cells should always be assessed.
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PMID:In vitro labeling strategies for identifying primary neural tissue and a neuronal cell line after transplantation in the CNS. 814 80

MutS, a DNA mismatch-binding protein, seems to be a promising tool for mutation detection. We present three MutS based approaches to the detection of point mutations: DNA retardation, protection of mismatched DNA against exonuclease digestion, and chimeric MutS proteins. DNA retardation in polyacrylamide gels stained with SYBR-Gold allows mutation detection using 1-3 microg of Thermus thermophilus his6-MutS protein and 50-200 ng of a PCR product. The method enables the search for a broad range of mutations: from single up to several nucleotide, as mutations over three nucleotides could be detected in electrophoresis without MutS, due to the mobility shift caused by large insertion/deletion loops in heteroduplex DNA. The binding of DNA mismatches by MutS protects the complexed DNA against exonuclease digestion. The direct addition of the fluorescent dye, SYBR-Gold, allows mutation detection in a single-tube assay. The limited efficiency of T4 DNA polymerase as an exonuclease hampers the application of the method in practice. The assay required 300-400 ng of PCR products in the range of 200-700 bp and 1-3 microg of MutS. MutS binding to mismatched DNA immobilised on a solid phase can be observed thanks to the activity of a reporter domain linked to MutS. We obtained chimeric bifunctional proteins consisting of T. thermophilus MutS and reporter domains, like beta-galactosidase or GFP. Very low detection limits for beta-galactosidase could theoretically enable mutation detection not only by the examination of PCR products, but even of genomic DNA.
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PMID:MutS as a tool for mutation detection. 1608 11