Tn5401 disruption of the spo0F gene, identified by direct chromosomal sequencing, results in CryIIIA overproduction in Bacillus thuringiensis

Malvar, Thomas; Baum, James A.

doi:10.1128/jb.176.15.4750-4753.1994

Cited by 33 publications

(25 citation statements)

References 12 publications

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“…The expression of cryIIIA is not dependent on sporulation-specific sigma factors either in B. subtilis (4) or in B. thuringiensis (48). Moreover, cryIIIA expression is increased and prolonged in mutant strains which are unable to initiate sporulation (e.g., spo0F [41] or spo0A [4,36,48]). Thus, cryIIIA activation is not regulated by the genes regulating sporulation initiation but rather by some regulator(s) affecting gene expression during the transition from exponential growth to the stationary phase.…”

Section: Transcriptional Mechanismsmentioning

confidence: 99%

How does Bacillus thuringiensis produce so much insecticidal crystal protein?

1995

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Section: Transcriptional Mechanismsmentioning

confidence: 99%

How does Bacillus thuringiensis produce so much insecticidal crystal protein?

1995

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“…More recently, a gene encoding a SpoOF-like protein has been characterized in B. thuringiensis (Malvar & Baum, 1994).…”

Section: S P O N C E T a N D O T H E R Smentioning

confidence: 99%

SpoOA represses transcription of the cry toxin genes in Bacillus thuringiensis

et al. 1997

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The DNA regions upstream from the genes encoding polypeptides of Bacillus thuringiensis subsp. israelensis larvicidal crystals (cry4A, cry4B, cry7 7A) contain sequences with similarities to the spoOA box of Bacillus subtilis (or 'OA' box) and the promoter recognized by the #-associated RNA polymerase of B. subtilis. Expression of cry-lacZ transcriptional fusions was analysed in various B. thuringiensis genetic backgrounds. The early transcription of the toxin genes was not sporulation-dependent, whereas the late-stage expression at tM was &dependent. Primer extension analysis confirmed that the c r y 4 and cry7 7-type toxin genes were weakly transcribed during the transition phase; expression analysis of a crylIA'-lacZ transcriptional fusion in B. subtilis sporulation mutants confirmed the involvement of the #-RNA polymerase. Primer extension analysis showed that in B. thuringiensis subsp. israelensis, the cry4A and cry77A gene transcription observed at the end of the growth stage was turned off at the beginning of the sporulation phase. The DNA region located upstream from the cry77A gene promoter including the putative 'OA' box was deleted. This led to a derepression of the expression of the cry77A operon. These results suggest that the cry4A, cry4B and cry77A toxin genes of B. thuringiensis subsp. israelensis are transcribed during the transition phase by the RNA polymerase associated with the # factor and are subject t o SpoOA repression.

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“…Another E E -driven operon, the glycogen operon, which is repressed by glucose in sporulating cells of B. subtilis, also supports the need for metabolic control of the stationary-phase phenomenon (19). In the light of the remarkable conservation of sigma subunits between B. thuringiensis and B. subtilis, the temporal regulation of sporulation in B. thuringiensis through the cascade of sigma factors is believed to be closely similar to that of B. subtilis (1,21,23,24). Homologs of several important transcription factors described in B. subtilis have been identified in B. thuringiensis also (1).…”

Section: Discussionmentioning

confidence: 82%

Loss of Catabolite Repression Function of HPr, the Phosphocarrier Protein of the Bacterial Phosphotransferase System, Affects Expression of the cry4A Toxin Gene in Bacillus thuringiensis subsp. israelensis

Khan

Banerjee-Bhatnagar

2002

J Bacteriol

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HPr, the phosphocarrier protein of the bacterial phosphotransferase system, mediates catabolite repression of a number of operons in gram-positive bacteria. In order to participate in the regulatory process, HPr is activated by phosphorylation of a conserved serine-46 residue. To study the potential role of HPr in the regulation of Cry4A protoxin synthesis in Bacillus thuringiensis subsp. israelensis, we produced a catabolite repression-negative mutant by replacing the wild-type copy of the ptsH gene with a mutated copy in which the conserved serine residue of HPr was replaced with an alanine. HPr isolated from the mutant strain was not phosphorylated at Ser-45 by HPr kinase, but phosphorylation at His-14 was found to occur normally. The enzyme I and HPr kinase activities of the mutant were not affected. Analysis of the B. thuringiensis subsp. israelensis mutant harboring ptsH-S45A in the chromosome showed that cry4A expression was derepressed from the inhibitory effect of glucose. The mutant strain produced both cry4A and 35 gene transcripts 4 h ahead of the parent strain, but there was no effect on 28 synthesis. In wild-type B. thuringiensis subsp. israelensis cells, cry4A mRNA was observed from 12 h onwards, while in the mutant it appeared at 8 h and was produced for a longer period. The total amount of cry4A transcripts produced by the mutant was higher than by the parent strain. There was a 60 to 70% reduction in the sporulation efficiency of the mutant B. thuringiensis subsp. israelensis strain compared to the wild-type strain.Biological control of dipteran pests in general and mosquitoes in particular has been a subject of primary importance for many years. Bacillus thuringiensis subsp. israelensis has been found to be the most effective microbial strain to date, possessing all the desirable properties of an ideal biocontrol agent. B. thuringiensis subsp. israelensis produces larvicidal crystal proteins in the stationary phase, concomitant with sporulation. The larvicidal activity of the parasporal crystals is attributed to the ␦-endotoxin, composed of at least four major polypeptide species of about 27, 72, 128, and 135 kDa, which act synergistically in the manifestation of toxicity (27,32). The high levels of toxin accumulation are controlled by a variety of mechanisms at the transcriptional, posttranscriptional, and posttranslational levels (2). The genes encoding different protein toxins are normally associated with large plasmids in B. thuringiensis subsp. israelensis (20,26) and are named cry4A, cry4B, cry11A, and cytA. cry4A and cry4B code for the 135-kDa and 125-kDa protoxins, respectively, which are activated by the gut proteases in the alkaline conditions of the insect gut.In sporulating cells of B. thuringiensis, the accumulation of large amounts of toxin proteins is achieved by expression from strong promoters associated with the gene. As in Bacillus subtilis, the developmental process is temporally and spatially regulated at the transcriptional level in B. thuringiensis by successive activati...

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Tn5401 disruption of the spo0F gene, identified by direct chromosomal sequencing, results in CryIIIA overproduction in Bacillus thuringiensis

Cited by 33 publications

References 12 publications

How does Bacillus thuringiensis produce so much insecticidal crystal protein?

How does Bacillus thuringiensis produce so much insecticidal crystal protein?

SpoOA represses transcription of the cry toxin genes in Bacillus thuringiensis

Loss of Catabolite Repression Function of HPr, the Phosphocarrier Protein of the Bacterial Phosphotransferase System, Affects Expression of the cry4A Toxin Gene in Bacillus thuringiensis subsp. israelensis

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