Regulation of pag gene expression in Bacillus anthracis: use of a pag-lacZ transcriptional fusion

Cataldi, Angel

doi:10.1016/0378-1097(92)90137-d

Cited by 15 publications

(24 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As noted previously (40), upstream ofpag there are exact (TATAAT) and nearly exact (TTGAAA versus TTGACA) matches to the -10 and -35 consensus sequences recognized by the primary housekeeping o# of B. subtilis RNA polymerase (27). The implication that pag is transcribed during exponential growth phase is consistent with a prior demonstration that the amount of lethal toxin parallels cell density (8) and with a recent report that expression from the pag promoter occurs throughout the exponential growth phase (4). Another notable feature of the putative pag promoter region is that the -10 and -35 sequences are potentially sequestered within an extended stem-loop structure, nucleotides 1722 to 1779 (40), having a AGf of -15.8 kcal (ca.…”

Section: Discussionsupporting

confidence: 89%

“…Bartkus and Leppla (1) reported that production of PA is transcriptionally regulated by bicarbonate, that a trans-acting factor is required for pag transcription, and that at least some of the genes involved are located on the toxin plasmid pXOl. Evidence for such a factor was also provided by Cataldi et al (4,5). Recently, two classes of B. anthracis insertion mutants altered in toxin production were described (15).…”

mentioning

confidence: 85%

See 1 more Smart Citation

Cloning and characterization of a gene whose product is a trans-activator of anthrax toxin synthesis

et al. 1993

View full text Add to dashboard Cite

The 184-kb Bacilus anthracis plasmid pXO0, which is required for virulence, contains three genes encoding the protein components of anthrax toxin, cya (edema factor gene), kef (lethal factor gene), and pag (protective antigen gene). Expression of the three proteins is induced by bicarbonate or serum. Using a pagklacZ transcriptional construct to measure pag promoter activity, we cloned in BaciUus subtilis a gene (alxA) whose product acts in trans to stimulate anthrax toxin expression. Deletion analysis located aIxA on a 2.0-kb fragment between cya and pag. DNA sequencing identified one open reading frame encoding 476 amino acids with a predicted Mr of 55,673, in good agreement with the value of 53 kDa obtained by in vitro transcriptiontranslation analysis. The cloned airA gene complemented previously characterized Tn917 insertion mutants UM23 tp29 and UM23 tp32 (J. M. Hornung and C. B. Thorne, Abstr. 91st Gen. Meet. Am. Soc. Microbiol. 1991, abstr. D-121, p. 98), which are deficient in synthesis of all three toxin proteins. These results demonstrate that the atxA product activates not only transcription of pag but also that of cya and lef. 3-Galactosidase synthesis from the pag-lacZ transcriptional fusion construct introduced into an insertion mutant (UM23 tp62) which does not require bicarbonate for toxin synthesis indicated that additional regulatory genes other than atxA play a role in the induction of anthrax toxin gene expression by bicarbonate.

show abstract

Section: Discussionsupporting

confidence: 89%

mentioning

confidence: 85%

Cloning and characterization of a gene whose product is a trans-activator of anthrax toxin synthesis

et al. 1993

View full text Add to dashboard Cite

show abstract

“…In B. anthracis, transcription of the genes encoding the virulence-associated capsule and anthrax tripartite toxin is activated by bicarbonate (Bartkus and Leppla, 1989;Cataldi et a/., 1992;Koehler et a/., 1994;Sirard et a/., 1994;Uchida et a/., 1993a), and bicarbonate-stimulated expression of both toxin and capsule genes is dependent on the trans-acting factors of atxA and acpA, respectively (Dai eta/., 1995;Vietri eta/., 1995). Because synthesis of these virulence factors responds to the same signal, bicarbonate, it seemed likely that there might exist some interaction or cross-talk between the two regulatory systems.…”

Section: Discussionmentioning

confidence: 99%

Cross‐talk to the genes for Bacillus anthracis capsule synthesis by atxA, the gene encoding the frans‐activator of anthrax toxin synthesis

Uchida

Makino

Sekizaki

et al. 1997

Molecular Microbiology

View full text Add to dashboard Cite

SummaryThe two major virulence factors of Bacillus anfhracis are the tripartite toxin and the polyglutamate capsule, which are encoded by genes on the large plasmids, pXOl and pX02, respectively. The genes atxA, located on pXO1, and acpA, located on pX02, encode positive trans-acting proteins that are involved in bicarbonatemediated regulation of toxin and capsule production, respectively. A derivative strain cured of pXOl produced less capsular substance than the parent strain harbouring both pXOl and pX02, and electroporation of the strain cured of pXOl with a plasmid containing the cloned afxA gene resulted in an increased level of capsule production. An acpA-null mutant was complemented by not only acpA but also the afxA gene. The cap region, which is essential for encapsulation, contains three genes capB, cape, and capA, arranged in that order. The afxA gene stimulated capsule synthesis from the cloned cap region. Transcriptional analysis of cap by RNA slot-blot hybridization and primer-extension analysis revealed that afxA activated expression of cap in trans at the transcriptional level. These results indicate that cross-talk occurs, in which the pXOl -located gene, atxA, activates transcription of the cap region genes located on pX02. We identified two major apparent transcriptional start sites, designated P1 and P2, located at positions 731 bp and 625 bp, respectively, upstream of the translationinitiation codon of caps. Transcription initiated from P1 and P2 was activated by both atxA and acpA, and activation appeared to be stimulated by bicarbonate. Deletion analysis of the upstream region of the cap

show abstract

“…Quantitative studies ofpag gene expression using B. anthracis strains harboring transcriptional fusions in trans have been conducted previously (1,3). It has been shown that bicarbonate activates pag expression throughout the exponential growth phase and maximally in the late log phase.…”

mentioning

confidence: 99%

The three Bacillus anthracis toxin genes are coordinately regulated by bicarbonate and temperature

1994

View full text Add to dashboard Cite

The two BaciUlls anthracis toxins are composed of three proteins, protective antigen, lethal factor, and edema factor. The structural genes for these three components are located on the virulence plasmid pXOl. We constructed transcriptional fusions between the regulatory region of each of these genes and acZ. Each construct was then inserted as a single copy at the corresponding toxin gene locus on pXOl, resulting in three isogenic strains. Two environmental factors, bicarbonate and temperature, were found to induce 3-galactosidase synthesis in each recombinant strain. Furthermore, the transcription of the three toxin genes appears to be coordinately regulated.

show abstract

Regulation of pag gene expression in Bacillus anthracis: use of a pag-lacZ transcriptional fusion

Cited by 15 publications

References 13 publications

Cloning and characterization of a gene whose product is a trans-activator of anthrax toxin synthesis

Cloning and characterization of a gene whose product is a trans-activator of anthrax toxin synthesis

Cross‐talk to the genes for Bacillus anthracis capsule synthesis by atxA, the gene encoding the frans‐activator of anthrax toxin synthesis

The three Bacillus anthracis toxin genes are coordinately regulated by bicarbonate and temperature

Contact Info

Product

Resources

About