Disease relevance of lacZ

• This leads to the activation of downstream promoter elements (TATA box and initiation, I, region) of three different regulated yeast promoters fused to the E. coli lacZ gene [1].
• A strain of Escherichia coli constructed by Shapiro has a segment of Mu bacteriophage DNA inserted between the araC and lacZ genes [2].
• Regulation of expression of genes coding for small, acid-soluble proteins of Bacillus subtilis spores: studies using lacZ gene fusions [3].
• In vivo inversion activity was measured by using a recombinant lambda phage which contains the H2 and lacZ genes under the control of the invertible region [4].
• The nucleotide sequences of the Klebsiella pneumoniae lacI and lacZ genes and part of the lacY gene were determined, and these genes were located and oriented relative to one another [5].

High impact information on lacZ

• Unique to trpR-lacZ bypassing is that the 55 nt long region must be translated in frame 0 to enable bypassing into the +1 frame [6].
• We have replaced the Hox-3.1 coding sequence with the E. coli lacZ gene by means of homologous recombination in embryonic stem cells and thus produced null mutant mice [7].
• Ribosome bypass of the untranslated region also occurs when a segment of gene 60 is fused to lacZ and expressed in E. coli [8].
• Expression plasmids containing the E. coli lacZ coding region preceded by a set of different ribosome-binding sites and put under transcriptional control of the leftward promoter of phage lambda (PL) were used to study the synthesis of lacZ mRNA [9].
• With transcriptional fusions between the lacZ gene or transposon mini-Mu and the target gene, expression of lux operons could be measured in the absence of light production [10].

Chemical compound and disease context of lacZ

• Escherichia coli strain MM18 cells containing malE-lacZ hybrid protein was reported to accumulate prolipoprotein when they were induced with maltose [Ito, K., Bassford, P. J. & Beckwith, J. (1981) Cell 24, 707-717] [11].
• Mu dX phage was used to isolate three gene fusions to the lacZ gene (soi::lacZ; soi for superoxide radical inducible) that were induced by treatment with superoxide radical anion generators such as paraquat and plumbagin [12].
• We measured the transcription elongation rate on two mRNA genes, i.e. infB and lacZ, and on a part of the rrnB gene under conditions when wild type (rel+) Escherichia coli and relaxed (relA) mutants were exposed to isoleucine starvation [13].
• Here we measure the frequency of UV-induced cyclobutane pyrimidine dimers at individual nucleotides within defined portions of two Escherichia coli genes, lacl and lacZ, at various times after irradiation [14].
• We also introduced a gene, kan, which confers kanamycin resistance, into lambda placMu50 and lambda placMu1, an analogous phage for constructing lacZ protein fusions (Bremer et al., J. Bacteriol. 158:1084-1093, 1984) [15].

Biological context of lacZ

• Analyses of a lacZ- papA gene fusion located a promoter upstream from papA within the cloned DNA [16].
• The nucleotide sequence of the lacZ gene coding for beta-galactosidase (EC 3.2.1.23) in Escherichia coli has been determined [17].
• The power of lac genetics can be applied to almost any bacterial system with gene fusions that hook any gene of interest to lacZ, which is the structural gene that encodes beta-galactosidase [18].
• The effect of the inserted DNA segment on the expression of the lacZ gene (in the presence and absence of arabinose) permits the localization of regulatory signals to discrete regions of the rplJL-rpoBC operon [19].
• If an insert is an ORF of the correct length, ompF and lacZ become realigned in frame, resulting in a LacZ+ gene that produces a tribrid protein with the translation product of the insert sandwiched between OmpF and beta-galactosidase [20].

Anatomical context of lacZ

• Translational fusions of dotA to the Escherichia coli phoA and lacZ genes indicated that DotA is an integral cytoplasmic membrane protein with eight membrane-spanning domains [21].
• The functional stability of the lacZ transcript is sensitive towards sequence alterations immediately downstream of the ribosome binding site [22].
• By analyzing reciprocal fusions between crdS and the reporter genes, lacZ and phoA, and assessing the sensitivity of CrdS in spheroplasts to proteinase K, CrdS was shown to be an integral membrane protein with seven transmembrane helices and an Nout-Cin disposition [23].
• Ethyl nitrosourea and methyl methanesulfonate mutagenicity in sperm and testicular germ cells of lacZ transgenic mice (Muta Mouse) [24].
• Three and 14 days after treatment, testes and sperm were collected for lacZ mutation analysis [24].

Associations of lacZ with chemical compounds

• Excision events that produce an in-frame fusion of lacZ to araB result in a cell (here designated Ara-Lac+) that can grow on lactose if arabinose is present as an inducer [2].
• In some of these strains the induction (with maltose) of lamB-lacZ hybrid protein synthesis was lethal because of membrane damage resulting from an incomplete export of this protein to the outer membrane [25].
• Using a narG-lacZ reporter fusion to evaluate narGHJI expression in vivo both the nitrate and anaerobic dependent controls were severely impaired in a himA mutant compared with the wild type strain [26].
• The sequence determination was aided by analysis of cyanogen bromide peptides obtained from a polypeptide fragment produced by a lacZ termination mutant strain [27].
• This approach allowed us to isolate lacZ fusions with the genes pelC, pelD, ogl and pem, encoding pectate lyases PLc and PLd, oligogalacturonate lyase and pectin methylesterase, respectively [28].

Physical interactions of lacZ

• Substitution of the nfrB ribosome binding site with that of the E. coli lacZ gene reduced production levels of nitroreductase [29].
• Another fusion gene was generated by inserting ceaB3 between the malE gene encoding maltose binding protein (mbp) and lacZ alpha of the pmal-c2 vector [30].
• Analysis of lacZ transcriptional fusions shows that the KdgR-binding sites negatively affect the expression of rsmB [31].

Regulatory relationships of lacZ

• Our findings indicate that the natural polarity of the operon (lacZ is expressed sixfold more strongly than lacA) is based on posttranslational effects and not on polarity of transcription [32].
• Using translational fusions to lacZ we found that DNA damage caused by mitomycin C induces expression of the dnaA and dnaQ genes [33].
• In these strains lacZ expression is regulated by the cytR repressor protein and is therefore induced by cytidine [34].
• Mutants in this class fail to produce the lamB-lacZ hybrid protein but retain the ability to express lacY, which is located distal to the hybrid gene [25].
• The influence of formamidopyrimidine-DNA glycosylase on the spontaneous and gamma-radiation-induced mutation spectrum of the lacZ alpha gene [35].

Other interactions of lacZ

• Analysis of reverse mutations in lacZ and forward nonsense mutations in lacI showed that the mutA strain has higher levels of A.T----T.A and G.C----T.A transversions, and to a lesser degree A.T----C.G transversions [36].
• This sequence is coupled to the lacZ gene of E. coli so that expression of beta-galactosidase requires ompF transcription and translation signals [20].
• We previously showed that heat-induced translation of sigma 32-beta-galactosidase fusion protein encoded by an rpoH-lacZ gene fusion was mediated by an mRNA secondary structure formed between two 5'-proximal segments (A and B) of rpoH coding sequence spanning some 200 nt [37].
• Induction of the lac operon in wild type Escherichia coli strains results in synthesis of a 16-kDa inner membrane protein in addition to the known products of the lacZ, lacY, and lacA genes [38].
• Using an ompC-lacZ fusion gene, the orientation of the cis-acting upstream sequence (OmpR-binding site) with respect to the canonical -35 and -10 regions (RNA polymerase-binding site) was changed [39].

Analytical, diagnostic and therapeutic context of lacZ

• We employed oligonucleotide-directed site-specific mutagenesis to dissect the promoter region of the gene and assayed the promoters separately for transcriptional ability using fusions to the lacZ gene [40].
• In addition, this resistance to H2O2 correlated well with reduced amount of DNA damage caused by H2O2, determined by the induction level of the recA :: lacZ fusion gene after treatment with H2O2 [41].
• Use of different types of cell culture medium resulted in a fivefold variation in hemA-lacZ expression during aerobic cell growth [42].
• Restriction mapping and RNA polymerase binding studies identified two regions within the fragment which exhibit promoter activity when fused to lacZ in pMC1403, a plasmid used to detect transcriptional and translational control signals [43].
• Several point mutations affecting translation initiation have been formerly characterized in this RBS, and we used Northern blots to study their effect upon the lacZ mRNA pattern [44].

References