Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D03345 (beta-Galactosidase)
 434 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of the thymidine-thymidylate kinase (HSV1-TK), (ATP: thymidine 5'-phosphotransferase; EC 2.7.1.21) of herpes simplex virus type 1 endows the host cell with a conditional lethal phenotype which depends on the presence of nucleoside analogues metabolized by this enzyme into toxic inhibitors of DNA replication. To generate a recombinant baculovirus that could be selected against by nucleoside analogs, the HSV1-tk coding sequence was placed under the control of the Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV) immediate early promoterm IE-1(0), and this construction was introduced via homologous recombination into the polyhedrin locus of AcMNPV. Two recombinant baculoviruses harboring this gene construct at the polyhedrin locus were isolated and tested for their ability to replicate in the presence of various concentrations of the nucleoside analog 9-(1,3-Dihydroxy-2-propoxymethyl)guanine (Ganciclovir). Neither Sf9 lepidopteran cell viability nor replication of wild type or beta-Galactosidase-expressing recombinant AcMNPVs were affected by concentrations of Ganciclovir up to 100 microM. In contrast, replication of the recombinant AcMNPV virus harboring the HSV1-tk gene was inhibited by Ganciclovir in a dose-dependent manner. The inhibition was detectable at 2 microM and complete at 100 microM. This property was exploited in model isolations aimed at purifying new recombinant viruses having lost this counter-selectable gene marker as a result of homologous recombination at the polyhedrin locus after cotransfection of the viral DNA with a replacement vector. After being propagated in the presence of Ganciclovir, the progeny of such co-transfections contained over 85% recombinant viruses, demonstrating that counter-selection of parental HSV1-tk-containing viruses by Ganciclovir constitutes a novel approach for recombinant baculovirus isolation.
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PMID:Replication inhibition by nucleoside analogues of a recombinant Autographa californica multicapsid nuclear polyhedrosis virus harboring the herpes thymidine kinase gene driven by the IE-1(0) promoter: a new way to select recombinant baculoviruses. 133 69

The low-Ca2+ response (Lcr) of Yersinia includes a regulatory cascade and a set of virulence-related proteins, one of which is the V antigen. The regulatory genes modulate both bacterial growth and expression of the virulence-related proteins in response to temperature and the presence of Ca2+ and nucleotides. In this study we defined a new Lcr locus, lcrR, in Yersinia pestis KIM. An lcrR mutant, obtained by insertion mutagenesis, failed to grow at 37 degrees C whether Ca2+ was present or not. However, it grew normally in the presence of ATP, showing that the Ca2(+)- and nucleotide-responsive mechanisms are separate in Y. pestis. The lcrR mutant was avirulent in mice, probably due to its compromised growth at 37 degrees C. beta-Galactosidase measurements and Northern (RNA blot) analysis revealed that lcrR transcription was regulated primarily by temperature. The DNA sequence of the lcrR locus contained a single open reading frame of 441 bases that could encode a protein with a molecular weight of 16,470 and a pI of 10.73. Expression of an lcrR-containing clone in Escherichia coli yielded a 16,000-molecular-weight protein. At 37 degrees C, the lcrR mutant strongly expressed V antigen and initiated lcrGVH transcription whether Ca2+ was present or not, indicating that this mutant had lost the transcriptional downregulation of lcrGVH shown by the parent in the presence of Ca2+. In the absence of Ca2+, the mutant failed to express LcrG, even though lcrGVH mRNA initiated upstream of lcrG at the normal sites. These data suggest that the lcrR locus is necessary for the regulation of LcrG expression in the absence of Ca2+. Therefore, this locus has a dual regulatory role in the low-Ca2+ response.
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PMID:lcrR, a low-Ca2(+)-response locus with dual Ca2(+)-dependent functions in Yersinia pestis. 169 96

Subunit A of the vacuolar H(+)-ATPase class is thought to be responsible for the ATP hydrolysis which drives proton-pumping. We report here the cloning and sequence determination of the first mammalian cDNA encoding a bovine vacuolar ATPase subunit A from an adrenal medulla cDNA library. Northern blots of bovine adrenal medulla RNA reveal a message of approximately 3.8 kb. The predicted peptide sequence, consisting of 618 amino acids with a calculated molecular weight of 68397 daltons, is similar to the sequences of the three known subunit A proteins. beta-Galactosidase-subunit A fusion proteins were immuno-decorated by an antiserum raised to the subunit A protein from corn coleoptile vacuoles.
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PMID:Structure and expression of subunit A from the bovine chromaffin cell vacuolar ATPase. 183 3

Escherichia coli K-12 produces at least two ATP-dependent proteases, Lon (La) and Clp (Ti), the latter consisting of a regulatory subunit (ClpA) and a proteolytic subunit (ClpP). The gene clpB encoding an analog of ClpA had been found at 57 min on the E. coli chromosome. Cloning and examination of novel heat shock promoters led us to identify a major clpB promoter specifically controlled by a heat shock sigma factor, sigma 32 (the rpoH [= htpR] gene product). beta-Galactosidase synthesis from a PclpB-lacZ operon fusion was transiently induced upon temperature shift from 30 to 42 degrees C, and the induction depended on the rpoH function. Chromosomal clpB transcripts also increased upon temperature upshift and were totally absent in the rpoH deletion strain. In the in vitro transcription experiments, the clpB promoter was specifically recognized and transcribed by RNA polymerase-sigma 32. Nucleotide sequencing and determination of mRNA start sites permitted us to identify a major heat shock promoter located upstream of the clpB coding sequence. The results clearly indicate that clpB expression is under direct control of sigma 32. Since ClpP was recently shown to be a sigma 32-dependent heat shock protein, the present finding suggests the possibility that a potential ATP-dependent protease, ClpB-ClpP complex, plays an important role against thermal stress in E. coli.
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PMID:Expression of ClpB, an analog of the ATP-dependent protease regulatory subunit in Escherichia coli, is controlled by a heat shock sigma factor (sigma 32). 190 60

Polyphosphate kinase (Ppk) catalyzes the formation of polyphosphate from ATP. We cloned the ppk gene (2,073 bp) from Acinetobacter sp. strain ADP1; this gene encodes a putative polypeptide of 78.6 kDa with extensive homology to polyphosphate kinase from Escherichia coli and other bacteria. Chromosomal disruption of ppk by inserting a transcriptionally fused lacZ does not affect growth under conditions of phosphate limitation or excess. beta-Galactosidase activity expressed from the single-copy ppk::lacZ fusion is induced 5- to 15-fold by phosphate starvation. An increased amount of ppk transcript (2.2 kb) was detected when cells were grown at a limiting phosphate concentration. Primer extension analysis revealed a regulated promoter located upstream of a second, constitutive promoter. Potential similarities of this regulation with the effects of PhoB and PhoR of E. coli are discussed.
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PMID:Transcription of ppk from Acinetobacter sp. strain ADP1, encoding a putative polyphosphate kinase, is induced by phosphate starvation. 950 29