Use of a lacZ gene fusion to determine the dependence pattern of sporulation operon spoIIA in spo mutants of Bacillus subtilis

A spoIIA::lacZ gene fusion has been used to investigate the dependence pattern of expression of the spoIIA operon during sporulation in Bacillus subtilis. beta-Galactosidase activity, encoded by the hybrid gene, begins to appear about 30 to 60 min after the induction of sporulation. spoIIA expression is dependent upon the products of all of the known spoO loci but on none of the 'later' loci tested. The beta-galactosidase activity falls after 1.5 h in Spo+ cells and in late-blocked mutants, but continued accumulation of the enzyme occurs in certain stage II mutants. Kinetic experiments suggest that the fall in activity may be, in part, the result of regulation at the level of translation. Mutations in several loci, spo0J, spoIIIF and spoVIC, delay expression of the operon by 1-3 h. The significance of these results in terms of models for the control of gene expression during sporulation is discussed.     

Use of a lacZ gene fusion to determine the dependence pattern and the spore compartment expression of sporulation operon spoVA in spo mutants of Bacillus subtilis

A spoVAA::lacZ gene fusion has been used to study expression of the spoVA operon during sporulation in Bacillus subtilis. beta-Galactosidase activity, encoded by the fusion gene, begins to be produced about 2.5 h after the induction of sporulation, well before the phenotypic consequences of spoVA mutations are manifested. spoVA expression is dependent on all of the known spo0 and spoII loci and on some of the 'early' spoIII loci, but not on 'later' loci. Several lines of evidence suggest that spoVA expression occurs only in the spore compartment. The implications of this observation for models of the overall regulation of gene expression during sporulation are discussed.     

Cloning and nucleotide sequence of the Brucella abortus groE operon.

The cloning and sequencing of the Brucella abortus groES and groEL genes are reported. The genes are adjacent on the Brucella chromosome, and presumably comprise a functional operon. Putative promoter and terminator sequences are also identified. The groES gene exhibits 60%, and the groEl gene 69%, sequence identity with the corresponding Escherichia coli genes.     

Cloning of sporulation gene spoIIG in Bacillus subtilis.

Two specialized transducing phages carrying a sporulation gene, spoIIG , of Bacillus subtilis were constructed from B. subtilis temperate phages p11 and phi 105 by the "prophage transformation" method. Restriction enzyme analysis and transformation experiments showed that the spoIIG gene was present on a 6.2 X 10(6)-dalton (6.2-Md) EcoRI fragment in both transducing phage genomes. Further analysis showed that spoIIG + transforming activity resides on a 2.25-Md EcoRI-BamHI fragment within the 6.2-Md EcoRI fragment. The 2.25-Md fragment was subcloned into the region between the EcoRI and BamHI sites of pUB110, and deletion plasmids lacking PstI or HindIII fragments within the 2.25-Md fragment were constructed. The recombinant plasmid carrying the intact spoIIG gene restored sporulation of strain HU1002 ( spoIIG41 recE4 ) to a frequency of 10(4) spores per ml and inhibited sporulation of strain 4309 ( spo + recE4 ) to a level of 10(3) spores per ml.     

clpC operon regulates cell architecture and sporulation in Bacillus anthracis

The clpC operon is known to regulate several processes such as genetic competence, protein degradation and stress survival in bacteria. Here, we describe the role of clpC operon in Bacillus anthracis. We generated knockout strains of the clpC operon genes to investigate the impact of CtsR, McsA, McsB and ClpC deletion on essential processes of B. anthracis. We observed that growth, cell division, sporulation and germination were severely affected in mcsB and clpC deleted strains, while none of deletions affected toxin secretion. Growth defect in these strains was pronounced at elevated temperature. The growth pattern gets restored on complementation of mcsB and clpC in respective mutants. Electron microscopic examination revealed that mcsB and clpC deletion also causes defect in septum formation leading to cell elongation. These vegetative cell deformities were accompanied by inability of mutant strains to generate morphologically intact spores. Higher levels of polyhydroxybutyrate granules accumulation were also observed in these deletion strains, indicating a defect in sporulation process. Our results demonstrate, for the first time, the vital role played by McsB and ClpC in physiology of B. anthracis and open up further interest on this operon, which might be of importance to success of B. anthracis as pathogen.     

Cloning of an early sporulation gene in Bacillus subtilis.

A 0.8-megadalton BglII restriction fragment of Bacillus licheniformis cloned into the BglII site of plasmid pBD64 can complement spo0H mutations of Bacillus subtilis. The clone was isolated by selecting for the Spo+ phenotype and antibiotic resistance, using the helper system described by Gryczan et al. (Mol. Gen. Genet. 177:459-467, 1980). The insert is functional in both orientations and thus presumably has its own promoter. A deletion generated within the 0.8-megadalton insert by HindIII restriction and subsequent religation eliminates the ability of the cloned fragment to complement spo0H mutations. The cloned B. licheniformis deoxyribonucleic acid segment specifies the synthesis, in minicells, of a polypeptide of approximately 27,000 daltons. This protein is observed with both orientations, but not when the HindIII deletion is present in the cloned B. licheniformis chromosomal fragment. We have also demonstrated that ribonucleic acid complementary to the cloned B. licheniformis sporulation gene is transcribed in B. licheniformis both during vegetative growth and sporulation.     

The pattern of sporulation in Anabaena circinalis and comments on the role of heterocysts in sporulation in blue-green algae.

Cells between two intercalary heterocysts differentiate at random into spores in A. circinalis. One or more cells, which fail to transform into spores, are present between the two adjacent spores, and these cells disorganize later. A critical C:N ratio regulates sporulation and heterocyst formation. During sporulation the reductive ability of the heterocyst gradually diminishes. It is concluded on the basis of this and other evidence that sporulation is regulated by interactions between heterocysts and vegative cells which are manifested in diverse patterns in different species of blue-green algae.     

Use of lacZ gene fusions to determine the dependence pattern of the sporulation gene spoIID in spo mutants of Bacillus subtilis

The spoIID gene, which is involved in Bacillus subtilis sporulation, was fused to the beta-galactosidase gene, lacZ, of Escherichia coli so that the expression of beta-galactosidase would be under the control of the spoIID locus. When the fused product was inserted into the B. subtilis chromosome, production of beta-galactosidase indicated that the spoIID gene was expressed 1.5 h after the start of sporulation. When the spoIID::lacZ fusion was inserted into the chromosome of sporulation mutants, all strains carrying spo0 lesions and those with mutations in spoIIA, spoIIE and spoIIG loci failed to make beta-galactosidase. The proposed provisional order of expression of operons governing stage II is spoIIA----[spoIIG, spoIIE]----[spoIID, spoIIB, spoIIF].