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)

1) The phage typing of Y. enterocolitica has been made on more than 4,000 strains of various origins by means of 2 sets of phages. The 1st one, composed of 12 phages extracted from lysogenic strains of the same species has permitted to distinguish 10 phages types numbered from I to VIII and from IXa to IXb among the 3,323 lysotypable strains on the 4,366 examinated. 2) The search of the beta-galactosidase has differentiated the phage type IXa in its 2 varieties, the IXa 1, beta-galactosidase negative and the IXa 2, beta-galactosidase positive. 3) The 1,043 untypable strains by the 1st set were forming 2 very different groups. One of them, the X was insensitive to the 12 phages of the 1st set; the other XI, showed such a variety of lytic reactions to the phages of the 1st set that it was impossible to consider the rare samples of each of them as phage types. 4) The group X, submitted to a "complementary phage typing" by means of a second set of phages isolated from sewage water, has been subdivised into about 20 undergroups, from which only, 7 have been studies up to now, numbered from X 1 to X 7...
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PMID:[New results on the phage typing of Yersinia enterocolitica, concerning more of 4 000 strains of various origins (author's transl)]. 102 81

Transgenic mice carrying the human cytomegalovirus immediate early gene promoter driving the E. coli lacZ gene displayed an unusual cell specific expression of beta-galactosidase during development. LacZ expression was first detected in cells lining the apex of the neural fold of day 8.5 embryos. By day 10 of gestation, expression was prominent in the spinal ganglia, the ganglia of cranial nerves V, VII, VIII, IX, and X, in a line of cells marking the ventrolateral pathway adjacent to the dermamyotome, and in a column of differentiated cells in the entire ventrolateral neural tube posterior to the mesencephalon. Expression was also found in the myotomes. Neural tube explants from day 8.5 embryos cultured in vitro showed lacZ expression in cells migrating away from the explant. We conclude that the HCMV-IEP-lacZ transgene is expressed in a subpopulation of neural crest cells and its early derivatives.
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PMID:Unusual cell specific expression of a major human cytomegalovirus immediate early gene promoter-lacZ hybrid gene in transgenic mouse embryos. 165 41

A regulatory element has been identified in the promoter region of the gene encoding the 11 kDa subunit VIII of the ubiquinol-cytochrome c oxidoreductase in Saccharomyces cerevisiae. The element, which is approximately 40 bp long and situated 185 bp upstream of the initiator ATG, is essential for induction of gene expression during growth in the presence of non-fermentable carbon sources. This is shown by the regulated synthesis of beta-galactosidase in yeast cells harbouring a CYC1-lacZ fusion gene, in which the CYC1 UAS's had been replaced by a 43 bp subunit VIII gene promoter fragment. In addition two DNA-binding activities, which may represent either separate factors or different forms of a single factor, have been detected. Both factors are abundant and they bind in a mutually exclusive fashion to a DNA sequence just upstream of the regulatory element. Although it is unlikely that these factors are directly involved in the response of the subunit VIII gene to catabolite repression, the position of their binding sites relative to the UAS and to the 3'-terminus of a gene located only 361 bp upstream suggest that they are important in modulating transcriptional activity of this region.
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PMID:Demarcation of a sequence involved in mediating catabolite repression of the gene for the 11 kDa subunit VIII of ubiquinol-cytochrome c oxidoreductase in Saccharomyces cerevisiae. 284 Jun 33

The role of the translational terminator and initiator signals arrangement for two adjacent genes in polycistronic mRNA has been studied. Semisynthetic beta-galactosidase gene (lacZ) of E. coli and fragment of phage M13 DNA (with promoter PVIII, gene IX, and part of gene VIII) were used for constructing of the IX-VIII-lacZ artificial polycistronic operon. Cloning of the constructs into pBR322 vector resulted in a number of pLZ381N plasmids differing by the mutual arrangement of gene VIII translation terminator codon and SD site and initiator codon (SD-ATG-region) of lacZ gene. The mutual arrangement of gene VIII terminator codon and SDlacZ-ATG region has been altered by means of deletions and insertions that have not affected lacZ translation initiation signals. The beta-galactosidase (beta-Gal) synthesis in E. coli harbouring different types of pLZ381N plasmids has been found to depend on type of cistron coupling (gene VIII and lacZ). The overlapping of terminator and initiator codons (ATGA) for genes VIII and lacZ (type I of polycistrons) provide approximately equal translational level for both cistrons. On the other side, levels of beta-Gal synthesis in case of polycistrons type II (gene VIII stop-codon position at the beginning of SDlacZ or 10 nucleotides upstream) were 20-30 times as high as for type I. Differences in beta-Gal levels have also been found for variants of VIII-lacZ coupling in types IV and III polycistrons (the SDlacZ-ATG region in 27-50 nucleotides downstream from the proximal cistron VIII stop-codon, which, in turn, is 41 nucleotides upstream this terminator). These data cannot be explained on the basis of possible secondary structure including the SDlacZ-ATG region and other parts of polycistronic mRNA. In all these cases similarly stable stem-loop structures have been found. Therefore, the arrangement of the translation termination and initiation signals for two adjacent genes in essential for distal gene translation efficiency. One can imagine that ribosome or its 30S subpartical, stalling on the proximal gene terminator codon, affects the distal gene translation initiation.
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PMID:[Effectiveness of distal gene translation in polycistrons depends upon the arrangement of regulatory signals on a template]. 323 97

Phage-specific transcription and subsequent RNA processing in Escherichia coli infected with the filamentous phage (f1, M13, fd) generate a pool of abundant and relatively long-lived phage mRNA species encoding the four adjacent genes V, VII, IX and VIII. Yet the products of gene V and gene VIII are synthesized at much higher levels than the gene VII and gene IX proteins. To ask if the translational initiation sites heading these genes show corresponding differences in activity and/or functional properties, we have purified a number of the phage mRNAs from cells infected with f1 and examined them in in vitro initiation reactions. The ribosome binding patterns obtained for the phage mRNA species and for smaller defined RNA fragments containing selected initiator regions reveal a large range in apparent ribosome binding strengths. The gene V and gene VIII sites are recognized efficiently in each mRNA species in which they are present. Gene IX site activity appears to be limited by local mRNA structure: the site has undetectable or low ribosome binding activity in all of the phage mRNA species, but is at least tenfold more active if the RNA sequences required to form a potential hairpin stem-and-loop 15 nucleotides upstream from the initiator AUG have been removed. The gene VII site shows no evidence of interaction with ribosomes in any phage mRNA or RNA fragment tested. The same striking differences in initiation activity were observed in vivo by cloning small f1 DNA fragments containing gene V or gene VII initiation site sequences to drive beta-galactosidase synthesis. High levels of a gene V-beta-galactosidase fusion protein are initiated at the V site, but no detectable synthesis occurs from the VII site. If the VII site is preceded by all of the information encoding the upstream gene V, however, modest amounts of a fusion protein initiated at the VII site are produced. The overall results, in accord with the observed yields of proteins in the phage-infected cell, provide strong evidence that the properties of these translational initiation sites determine in a significant way the differential expression of phage f1 genes V, VII, IX and VIII.
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PMID:Translational control of phage f1 gene expression by differential activities of the gene V, VII, IX and VIII initiation sites. 344 Oct 7

The mtr gene of Escherichia coli K-12 encodes an inner membrane protein which is responsible for the active transport of trypotophan into the cell. It has been proposed that the Mtr permease has a novel structure consisting of 11 hydrophobic transmembrane spans, with a cytoplasmically disposed amino terminus and a carboxyl terminus located in the periplasmic space (J.P. Sarsero, P. J. Wookey, P. Gollnick, C. Yanofsky, and A.J. Pittard, J. Bacteriol. 173:3231-3234, 1991). The validity of this model was examined by the construction of fusion proteins between the Mtr permease and alkaline phosphatase or beta-galactosidase. In addition to the conventional methods, in which the reporter enzyme replaces a carboxyl-terminal portion of the membrane protein, the recently developed alkaline phosphatase sandwich fusion technique was utilized, in which alkaline phosphatase is inserted into an otherwise intact membrane protein. A cluster of alkaline phosphatase fusions to the carboxyl-terminal end of the Mtr permease exhibited high levels of alkaline phosphatase activity, giving support to the proposition of a periplasmically located carboxyl terminus. The majority of fusion proteins produced enzymatic activities which were in agreement with the positions of the fusion sites on the proposed topological model of the permease. The synthesis of a small cluster of hybrid proteins, whose enzymatic activity did not agree with the location of their fusion sites within putative transmembrane span VIII or the preceding periplasmic loop, was not detected by immunological techniques and did not necessitate modification of the proposed model in this region. Slight alterations may need to be made in the positioning of the carboxyl-terminal end of transmembrane span X.
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PMID:Membrane topology analysis of Escherichia coli K-12 Mtr permease by alkaline phosphatase and beta-galactosidase fusions. 781 18

The calcium-stimulated adenylyl cyclases (ACs) play a central role in stimulus-dependent modification of synaptic function. The type VIII AC (AC8) is one of three mammalian calcium-stimulated isoforms, each of which is expressed in a region-specific manner in the CNS. To delineate the DNA sequences responsible for appropriate targeting of AC8 expression, we report here the complete structure of the AC8 gene and define the pattern of expression of the full-length cDNA and its splice variants. In addition to expression within the brain, robust expression of AC8 was also found in the lung. By in situ hybridization, we have found the highest expression of AC8 mRNA within the olfactory bulb, thalamus, habenula, cerebral cortex, and hypothalamic supraoptic and paraventricular nuclei. By generating transgenic mice whose expression of beta-galactosidase is controlled by the AC8 5'-flanking DNA sequences, we demonstrate that the DNA sequences within the 10 kb preceding exon 1 are critical for establishment of this region-specific pattern. This spectrum of sites of production is unique to AC8 among the calcium-stimulated adenylyl cyclases and suggests nonredundant functions with other adenylyl cyclases in neuroendocrine regulation and/or behavior.
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PMID:The 5'-flanking region of the mouse adenylyl cyclase type VIII gene imparts tissue-specific expression in transgenic mice. 1006 58

During mammalian spermatogenesis, the transcription of several genes in Sertoli cells is turned on and off as the adjacent male germ cells progress through the stages of the cycle of the seminiferous epithelium. A requirement for defining how germ cells regulate this process is the identification of a promoter that confers, in vivo, accurate, stage-specific gene expression in Sertoli cells. To date, such a promoter has not been identified. Using transgenic mice, we show that the 3-kilobase genomic fragment immediately upstream of the rat cathepsin L translation start site directs expression of the reporter gene, beta-galactosidase, only in Sertoli cells. The expression pattern of the reporter gene recapitulated that of the endogenous gene in Sertoli cells as 75% of the seminiferous tubules that contained X-gal positive Sertoli cells were at stages VI-VIII and beta-galactosidase enzymatic activity was 4-fold higher in mature testes compared with immature testes. This is, to our knowledge, the first identification of a promoter region that contains all of the regulatory elements required for accurate, stage-specific gene expression in Sertoli cells.
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PMID:A 3-kilobase region derived from the rat cathepsin L gene directs in vivo expression of a reporter gene in sertoli cells in a manner comparable to that of the endogenous gene. 1260 58

The membrane topology of the plasmid-encoded Pseudomonas aeruginosa ChrA protein, which effluxes chromate ions, was determined by the analysis of translational fusions with reporter enzymes alkaline phosphatase and beta-galactosidase. A novel 13-TMS (transmembrane segments) topology, with the N-terminus located in the cytoplasm and the C-terminus in the periplasmic space, was consistent with the enzyme activities determined in both Escherichia coli and P. aeruginosa. Alignment of the two halves of ChrA showed significant sequence homology, with TMS I, II, III, IV, V and VI displaying similarity to TMS VIII, IX, X, XI, XII and XIII, respectively, although with opposite membrane orientations. This suggests that ChrA arose from the duplication of a gene encoding a 6-TMS ancestral protein, followed by the insertion of extra TMS VII. These data also suggest that the two halves of ChrA may carry out distinct functions for the transport of chromate.
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PMID:Membrane topology of the chromate transporter ChrA of Pseudomonas aeruginosa. 1692 73