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Query: KEGG:D03345 (beta-Galactosidase)
 434 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have constructed a shuttle plasmid for Bacillus megaterium and Escherichia coli that contains the promoter and repressor gene of the B. megaterium-borne operon for xylose utilization. A polylinker downstream of the promoter allows versatile cloning of genes under its transcriptional control. We have placed gdhA (encoding glucose dehydrogenase) from B. megaterium, lacZ (encoding beta-galactosidase) from E. coli, mro (encoding mutarotase) from Acinetobacter calcoaceticus, and human puk (encoding single-chain urokinase-like plasminogen activator, rscuPA) under xylose control in this vector. All four genes were between 130-fold and 350-fold inducible by 0.5% xylose in the growth medium in B. megaterium. Enzymatically active glucose dehydrogenase and mutarotase accumulated to 20% and 30% of the total soluble protein, respectively. beta-Galactosidase and rscuPA were also expressed at a high level. A gel analysis of the products demonstrated their proteolytic stability in the cytoplasm, even up to 5 h after induction. The expression properties of this new host-vector system are discussed in comparison to the ones available for B. subtilis and E. coli.
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PMID:Inducible high-level expression of heterologous genes in Bacillus megaterium using the regulatory elements of the xylose-utilization operon. 136 76

Bacterial spores are highly resistant to killing by UV radiation and exhibit unique DNA photochemistry. UV irradiation of spore DNA results in formation of spore photoproduct (SP), the thymine dimer 5-thyminyl-5,6-dihydrothymine. Repair of SP occurs during germination of Bacillus subtilis spores by two distinct routes, either by the general nucleotide excision repair (uvr) pathway or by a novel SP-specific monomerization reaction mediated by the enzyme SP lyase, which is encoded by the spl gene. Repair of SP occurs early in spore germination and is independent of de novo protein synthesis, suggesting that the SP repair enzymes are synthesized during sporulation and are packaged in the dormant spore. To test this hypothesis, the expression of a translational spl-lacZ fusion integrated at the spl locus was monitored during B. subtilis growth and sporulation. beta-Galactosidase expression from the spl-lacZ fusion was silent during vegetative growth and was not DNA damage inducible, but it was activated at morphological stage III of sporulation specifically in the forespore compartment, coincident with activation of expression of the stage III marker enzyme glucose dehydrogenase. Expression of the spl-lacZ fusion was shown to be dependent upon the sporulation-specific RNA polymerase containing the sigma-G factor (E sigma G), as spl-lacZ expression was abolished in a mutant harboring a deletion in the sigG gene and restored by expression of the sigG gene in trans. Primer extension analysis of spl mRNA revealed a major extension product initiating upstream from a small open reading frame of unknown function which precedes spl, and it revealed two other shorter minor extension products. All three extension products were present in higher quantities during sporulation and after sigG induction. The three putative transcripts are all preceded by sequences which share homology with the consensus sigma-G factor-type promoter sequence, but in vitro transcription by purified sigma-G RNA polymerase was detected only from the promoter corresponding to the major extension product. The open reading frame-spl operon therefore appears to be an additional member of the sigma-G regulon, which also includes as members the small, acid-soluble spore proteins which are in large part responsible for spore DNA photochemistry. Therefore, sporulating bacteria appear to coordinately regulate genes whose products not only alter spore DNA photochemistry but also repair the major spore-specific photoproduct during germination
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PMID:Temporal regulation and forespore-specific expression of the spore photoproduct lyase gene by sigma-G RNA polymerase during Bacillus subtilis sporulation. 802 Nov 81