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)

A 100-kDa DNA binding protein was found to be dramatically up-regulated upon the mitogenic stimulation of murine splenocytes with bacterial lipopolysaccharide (LPS). The induced DNA binding protein was also found to exhibit moderate binding specificity for the immunoglobulin isotype switch DNA repeats. Furthermore, the induction of the 100-kDa protein by LPS was found to be mediated by both an increase in the protein's stability and an increase in the synthesis of the protein. In vitro phosphorylation experiments revealed that the 100-kDa DNA binding protein was one of the most heavily phosphorylated proteins in both lymphoid and nonlymphoid nuclear extracts. Although this in vitro phosphorylation initially appeared to be mediated by a potent nuclear kinase activity, it was later determined that a significant part of the detected labeling was due to the direct binding of ATP by the 100-kDa protein. Antibodies raised to the 100-kDa DNA binding protein were used to isolate cDNA clones from a lymphocyte cDNA lambda gt11 expression library. Nucleotide sequence analysis revealed that the cloned cDNAs were identical to the mouse nucleolin gene. The beta-galactosidase fusion proteins (encoded by exons 3-14 of nucleolin) and a more severely truncated 45-kDa protein (encoded by exons 5-14 of nucleolin) were both found to bind strongly to DNA and ATP. Furthermore, the strength of DNA binding was found to be highly dependent on the overall dG content of the DNA probes. Our experiments also revealed that apart from binding ATP and G-rich DNA, nucleolin directly bound GTP, dATP, and dGTP, but not dCTP, dTTP, or dUTP. Computer analysis revealed that the putative ATP binding domains appear to fall within two of the phylogenetically conserved RNA binding domains of nucleolin.
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PMID:The murine nucleolin protein is an inducible DNA and ATP binding protein which is readily detected in nuclear extracts of lipopolysaccharide-treated splenocytes. 769 29

The effects of deoxynucleoside triphosphate (dNTP) imbalances on the fidelity of human immunodeficiency virus type 1 (HIV-1) replication were investigated. Using detergent permeabilized virions and biased dNTP concentrations different types of hypermutants were readily produced. However, the mutant spectrum was different from naturally occurring hypermutants demonstrating that the host cell may restrict variation. Using a genetic screen based on the blue/white beta-galactosidase complementation assay, G --> A hypermutants were recovered from HIV-infected thymidine treated U937 cells. Furthermore, hypermutants were recovered from 1 to 2% of resting or activated peripheral blood mononuclear cells indicating that small proportions of primary cells had distorted intracellular [dTTP] and [dCTP]. Such imbalances may underlie a proportion of somatic and germline point mutations and shape to some extent the evolution of mammalian and viral genomes.
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PMID:HIV genetic variation is directed and restricted by DNA precursor availability. 923 17

Classical late-infantile neuronal ceroid lipofuscinosis (LINCL) is caused by mutations in tripeptidyl peptidase I (TPP-I), a pepstatin-insensitive lysosomal protease, resulting in neurodegeneration, acute seizures, visual and motor dysfunction. In vitro studies suggest that TPP-I is secreted from cells and subsequently taken up by neighboring cells, similar to other lysosomal enzymes. As such, TPP-I is an attractive candidate for enzyme replacement or gene therapy. In the present studies, we examined the feasibility of gene transfer into mouse brain using recombinant adenovirus (Ad), feline immunodeficiency virus (FIV) and adeno-associated virus (AAV) vectors expressing TPP-I, after single injections into the striatum or cerebellum. A dual TPP-I- and beta-galactosidase-expressing adenovirus vector (AdTTP-I/nlsbetagal) was used to distinguish transduced (beta-galactosidase positive) cells from cells that endocytosed secreted TTP-I. Ten days after striatal injection of AdTTP-I/nlsbetagal, beta-galactosidase-positive cells were concentrated around the injection site, corpus callosum, ependyma and choroid plexus. In cerebellar injections, beta-galactosidase expression was confined to the region of injection and in isolated neurons of the brainstem. Immunohistochemistry for TPP-I expression showed that TPP-I extended beyond areas of beta-galactosidase activity. Immunohistochemistry for TTP-I after FIVTTP-I and AAV5TTP-I injections demonstrated TPP-I in neurons of the striatum, hippocampus and Purkinje cells. For all three vectors, TPP-I activity in brain homogenates was 3-7-fold higher than endogenous levels in the injected hemispheres. Our results indicate the feasibility of vector-mediated gene transfer of TPP-I to the CNS as a potential therapy for LINCL.
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PMID:Viral-mediated delivery of the late-infantile neuronal ceroid lipofuscinosis gene, TPP-I to the mouse central nervous system. 1252 35

A genetic screen based on the blue-white beta-galactosidase complementation assay designed to detect G-->A mutations arising during RNA-dependent DNA synthesis was used to compare the fidelity of mutant human immunodeficiency virus type 1 reverse transcriptases (RTs) with the mutations M230L and M230I with the wild-type enzyme, in the presence of biased deoxynucleoside triphosphate (dNTP) pools. The mutant RTs with the M230L and M230I changes were found to be 20 to 70 times less faithful than the wild-type RT in the presence of low [dCTP]/[dTTP] ratios but showed similar fidelity in assays carried out with equimolar concentrations of each nucleotide. Biased dNTP pools led to short tandem repeat deletions in the target sequence, which were also detectable with the assay. However, deletion frequencies were similar for all of the RTs tested. The reported data suggest that RT pausing due to the low dNTP levels available in the RT reaction mixture facilitates strand transfer, in a process that is not necessarily mediated by nucleotide misinsertion.
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PMID:Increased G-->A transition frequencies displayed by primer grip mutants of human immunodeficiency virus type 1 reverse transcriptase. 1469 33