TRANSCRIPTIONAL REGULATION OF THE PROTECTIVE ANTIGEN GENE OF BACILLUS-ANTHRACIS
TRANSCRIPTIONAL REGULATION OF THE PROTECTIVE ANTIGEN GENE OF BACILLUS-ANTHRACIS
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DOI：
10.1128/iai.57.8.2295-2300.1989
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发表时间：
1989-08-01
影响因子：
3.1
通讯作者：
LEPPLA, SH
中科院分区：
文献类型：
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作者：
BARTKUS, JM;LEPPLA, SH
碳酸氢盐是生产炭疽芽孢杆菌的主要毒力因子，毒素和荚膜所必需的。在这项研究中，我们研究了刺激保护性抗原（PA）产生的基础，保护性抗原是由质粒pXO1编码的两种炭疽毒素的核心成分。在添加和不添加碳酸氢盐的培养基中生长的炭疽芽孢杆菌制备的RNA检测PA mrNA。数据显示，在最小培养基中，需要碳酸氢盐来增加PA基因（pag）的转录。在富培养基中，pag的转录水平较低，并且不能通过添加碳酸氢盐来刺激。为了进一步表征pag转录调控所需的因子，将pag的启动子区域融合到载体pPL703的氯霉素乙酰转移酶基因（cat-86）上，并通过电穿孔转化为炭疽杆菌的pXO1+ (Tox+)和pXO1- (Tox-) st rains。在这些背景下，对pag-cat-86融合产生的氯霉素乙酰转移酶的分析证实了杂交得到的结果。通过这种融合获得的数据还显示，在炭疽芽孢杆菌毒力菌株中发现的大毒素质粒pXO1是碳酸氢盐刺激pag转录所必需的。这一结果表明存在一种反式作用因子参与了pag转录的激活。
Bicarbonate is required for production of the major virulence factors, the toxins and capsule, of Bacillus anthracis. In this study we examined the basis for stimulation of production of protective antigen (PA), a central component of the two anthrax toxins encoded by plasmid pXO1. RNA prepared from B. anthracis grown in media with and without added bicarbonate was probed for PA mrNA. Data showed that bicarbonate was required for increased transcription of the PA gene (pag) in minimal medium. Transcription of pag was low in rich medium and could not be stimulated by the addition of bicarbonate. To characterize further the factors required for transcriptional regulation of pag, the promoter region of pag was fused to the chloramphenicol acetyltransferase gene (cat-86) of vector pPL703 and transformed by electroporation into pXO1+ (Tox+) and pXO1- (Tox-) st rains of B. anthracis. Analysis of chloramphenicol acetyltransferase produced by the pag-cat-86 fusion in each of these backgrounds confirmed the results obtained by hybridization. Data obtained with this fusion also revealed that the large toxin plasmid, pXO1 found in virulent strains of B. anthracis, was required for stimulation of transcription of pag by bicarbonate. This result suggests the existence of a trans-acting factor that is involved in the activation of pag transcription.