Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

In this study we demonstrate a hitherto undescribed phenomenon, namely that thymus-independent type-2 antigens (TI-2 Ag) localize in splenic follicles within 1 h after administration. The follicular localization of 2,4,6-trinitrophenyl (TNP)-Ficoll was not antibody mediated. In addition in case of high-dose administration we observed a relatively large amount of TI-2 Ag in marginal zone macrophages. However, after low-dose administration we observed a preferential localization of TNP-Ficoll in the splenic follicles. Detection of TNP-haptenated Ag in cryostat sections of murine spleens was performed with a high-affinity TNP-specific monoclonal antibody conjugated to beta-galactosidase. Within minutes after injection the TI-2 Ag localized in the marginal zone, attached to marginal zone macrophages and B cells. Twenty minutes after injection the Ag was also detected in the follicles and gradually accumulated there until 7 h after injection. Thereafter, the amount of follicular Ag gradually decreased but was still detectable up to 14 days after immunization. The follicular localization of TNP-Ficoll was complement dependent in contrast to the binding to and uptake by marginal zone macrophages. Double staining revealed that Ag was bound by macrophages, B cells and follicular dendritic cells. Haptenated thymus-dependent (TD) Ag localized exclusively in the red pulp macrophages. In vivo macrophage elimination drastically increased the amount of TNP-Ficoll in the follicles, and enhanced the humoral immune response at low doses of Ag. Moreover, complement deprivation of mice abrogated the localization of TI-2 Ag in the follicles, and led to a decreased humoral TI-2 immune response. In conclusion, we demonstrate for the first time that TI-2 Ag localize in follicles. Moreover, the presented results provide further evidence that B cells and follicular localized Ag play an important role in the induction of humoral TI-2 immune responses.
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PMID:Complement-mediated follicular localization of T-independent type-2 antigens: the role of marginal zone macrophages revisited. 154 18

Prothymosin alpha is a highly acidic protein which lacks an amino-terminal signal peptide, yet was once thought to be a precursor for thymosin alpha 1, a putative peptide hormone secreted by the thymus. Here, two lines of evidence are presented that strongly implicate prothymosin alpha as a nuclear protein: 1) in COS cells transfected with the human prothymosin alpha gene copious amounts of prothymosin alpha were present in sealed nuclei obtained by treating these cells with cytochalasin B and enucleating them centrifugally. 2) Constructs in which human prothymosin alpha nucleic acid sequences were fused in-frame either near the amino terminus of the beta-galactosidase gene in pCH110 or at the carboxyl terminus, when expressed in COS cells, resulted in nuclear localization of the fusion protein; indirect immunofluorescence in situ was used as the assay. The basic cluster of amino acids at the carboxyl terminus of prothymosin alpha, TKKQKT, has been identified as part of the nuclear targeting signal, whereas the basic cluster of amino acids situated within the thymosin alpha 1 sequence at the amino terminus failed to effect nuclear transport.
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PMID:Nuclear targeting of prothymosin alpha. 189 69

We have used the 1.1 kilobases of the 5' upstream region of the platelet factor four (PF4) gene coupled to the prokaryotic beta-galactosidase gene to generate two lines of transgenic mice that express this construct. Studies of blood, bone marrow, spleen, and thymus reveal that platelets are the only circulating blood cells and megakaryocytes are the only hematopoietic precursor cells that possess the prokaryotic enzyme. The lack of transgene expression in brain, heart, intestine, kidney, liver, lung, and skeletal muscle was established by in situ staining of tissue sections as well as kinetic assay of tissue homogenates. These data suggest that this domain of the PF4 promoter contains most, if not all, of the tissue-specific region of the gene. Unexpectedly, the adrenal gland exhibits approximately 2% of the levels of beta-galactosidase possessed by megakaryocytes and the distribution of the prokaryotic enzyme corresponds to the location of mineralocorticoid-secreting cells. This result implies that either the PF4 gene is transcribed at low levels in specialized adrenal cells or that these specialized endocrine cells possess trans-acting factors similar to those that control the megakaryocyte promoter. The selective high-level expression of transgenes linked to the PF4 promoter should allow us to augment or suppress the in vivo levels of critical components in megakaryocytes and platelets and subsequently ascertain the effects of these modifications.
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PMID:Selective targeting of gene products with the megakaryocyte platelet factor 4 promoter. 189 30

We assayed in the yeast S. cerevisiae the transcriptional transactivation activity of the c-myb products encoded by a normal thymus cDNA and of an aminoterminally truncated version of it (minus 58 amino acids) corresponding to the cDNAs isolated from lymphoma and leukemia cells from different origins. Both proto-oncogene products were expressed under the control of the galactose inducible GAL10 promoter. The reporter system used to monitor the transactivation potential of the myb products consisted of a CYCl-lacZ gene fusion in which the UASCYC signals were replaced by one or multiple copies of the myb recognition element (mRE). As shown by Northern blot analyses and by primer extension experiments both c-myb products increase the level of beta-galactosidase transcription. Interestingly, the c-myb product corresponding to lymphoma cDNAs stimulates transcription four to five times more efficiently than does the normal thymic c-myb product.
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PMID:Two c-myb proteins differing by their aminotermini exhibit different transcriptional transactivation activities (yeast/reporter-effector system). 199 38

A continuous fluorometric neuraminidase assay has been developed. Within the pH range optimal for neuraminidases (from 3 to 6) the fluorescence intensity of 4-methylumbelliferone exceeds that of the glycoside 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid about 50 times (at lambda Ex = 335 nm and lambda Em = 445 nm), allowing the precise, simple and time-saving continuous fluorometric registration of enzymatically released 4-methylumbelliferone. In juvenile calf thymus a neuraminidase consisting of two components differing in pH optima and resistence to freezing and to detergents could be found. A beta-galactosidase activity in juvenile calf thymus could be proved by the same assay procedure using the synthetic substrate 4-methylumbelliferyl-beta-D-galactopyranoside.
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PMID:Neuraminidase in juvenile calf thymus: determination and characterization by a continuous fluorometric assay procedure. 211 77

Calf thymus DNA and M13mp9 RF DNA were modified with [ring-3H]2-naphthyl isocyanate (NIC) and analyzed by reverse-phase HPLC following enzymatic hydrolysis. In each case, essentially, a single radioactive component, which co-chromatographed with authentic N4-2-naphthyl-carbamoyl-2'-deoxycytidine (NCdC), was detected. In order to explore the biological potential of this adduct, mp9 RF DNA modified with NIC was introduced into Escherichia coli strains using a calcium chloride technique. The plaque-forming efficiencies of DNA decreased with increasing adduct level, and the decreases were more pronounced in Uvr endonuclease-deficient strains (i.e. AB1886, uvrA; AB1885, uvrB; AB1884, uvrC) as compared to JM103 (Uvr endonuclease proficient) and JM101 RH03 (recA). These results suggest that these lesions, NCdC adducts, can be removed by the Uvr endonuclease repair system. Mutations were detected as the loss of ability of the bacteriophage to complement the defective beta-galactosidase of the host cells. Induction of SOS functions in the host cells enhanced the mutation frequency to 0.089%, i.e. greater than or equal to 4-fold greater than in non-SOS-induced cells, in transfections with RF DNA that contained 100 adducts/molecule. The mutagenic potency of this cytidine lesion is lower than that of the guanine-C8 adducts of 2-aminofluorene and 2-acetylaminofluorene as reported previously for this mutagenesis system.
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PMID:Characterization and genotoxicity of DNA adducts caused by 2-naphthyl isocyanate. 222 33

Antibodies raised to a mixture of the 46 and 48 kDa rat CNS 2',3'-cyclic nucleotide 3-phosphodiesterases (CNPs) recognized apparently identical proteins in peripheral nervous system (PNS), thymus, and circulating blood lymphocytes. These antibodies were used to identify, in a rat brain phage lambda gt11 expression library, cDNA clones encoding beta-galactosidase-CNP fusion proteins, some of which showed CNP activity. In RNA blots, the subcloned CNP cDNA inserts hybridized to mRNAs of approximately 2400 and approximately 2800 nucleotides (nts), and to a approximately 2500 nt mRNA from thymus. Several nonexpressing CNP cDNAs were identified by plaque hybridization, and the mRNA transcribed in vitro from one of these cDNAs (pCNP7) encoded a complete 46 kDa CNP polypeptide. Examination of the deduced amino acid sequence revealed an apparent homology to cAMP binding sites in several other proteins. A 373 bp segment from the 5' end of this pCNP7 hybridized only to the 2800 nt nervous system mRNAs, thus revealing that not all CNP mRNAs share the same 5'-ends. Genomic DNA blots probed with CNP cDNAs suggest that there is a single gene which can be alternatively spliced to produce the various mRNA transcripts in the nervous and lymphoid tissues.
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PMID:Molecular cloning of a 2',3'-cyclic nucleotide 3'-phosphodiesterase: mRNAs with different 5' ends encode the same set of proteins in nervous and lymphoid tissues. 304 Sep 24

A calf thymus cDNA expression library was constructed in the EcoRI site of lambda gt11 and probed with an antibody raised against calf thymus DNA polymerase alpha. Three classes of antibody-reactive clones were isolated. The largest class carried a 1.9 kilobase calf cDNA insert and expressed a 165-175 kilodalton beta-galactosidase:calf fusion protein which displayed DNA polymerase activity. The characteristic responses of the polymerase activity to alpha-specific inhibitors and antibodies identified the 1.9 kilobase cDNA as a sequence specifically derived from the structural gene encoding the pol alpha catalytic core.
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PMID:Cloning and expression of a cDNA encoding a catalytically active fragment of calf thymus DNA polymerase alpha. 309 17

The bactericidal activity of Tinopal AN [1,1-bis(3,N-5-dimethyl-benzoxazol-2-yl)-methine p-toluene sulphonate] was shown to be due to a mechanism entirely independent of its inhibitory effects upon NADH dehydrogenase which were reported previously. Whereas the compound had no significant effect upon DNA synthesis in Escherichia coli D22, RNA and protein synthesis were immediately and markedly inhibited. In confirmation, Tinopal AN caused an immediate cessation in inducible beta-galactosidase synthesis in the same organism. An in vitro assay of the transcription of calf-thymus DNA by purified E. coli RNA polymerase showed that this process was inhibited by Tinopal AN.
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PMID:The antibacterial action of Tinopal AN. 620

Subacute experiments were made to examine the effect of the grain contaminated with Fusarium sporotrichiella on the activity of organelle-specific enzymes of the liver, thymus, spleen, bone marrow and blood serum of rats (beta-N-acetylglucosaminidase, alpha-mannosidase, beta-galactosidase, arylsulfatases A and B, succinate dehydrogenase, glucose-6-phosphatase, alkaline phosphatase, ketoso-1-phosphate aldolase) and on the protein content. The feeding of the grain provoked an early appearance of the symptoms of intoxication and a change in the activity of organelle-specific enzymes manifesting in the activation of lysosomal hydrolases in the thymus, bone marrow and spleen and in a decrease in the blood serum activity of the most enzymes investigated.
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PMID:[Enzyme characteristics of food poisoning caused by grain contaminated with Fusarium sporotrichiella]. 642 31


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