EXPRESSION OF COMPETENCE GENES IN BACILLUS-SUBTILIS
EXPRESSION OF COMPETENCE GENES IN BACILLUS-SUBTILIS
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DOI：
10.1128/jb.169.7.3110-3117.1987
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发表时间：
1987-07-01
影响因子：
3.2
通讯作者：
DUBNAU, D
中科院分区：
文献类型：
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作者：
ALBANO, M;HAHN, J;DUBNAU, D
以Tn917lacZ为诱变剂构建了一组枯草芽孢杆菌感受态（com）突变体。在大约一半的突变体中，转座子上的无启动子 lacZ 元件受到推定的 com 启动子的控制。通过使用β-半乳糖苷酶标签来研究突变体com基因的表达。其中两个突变基因（以 com-124 和 com-138 为代表）在所有测试的培养基中在生长周期早期表达，并且不依赖于 spo0A 或 spo0H 产物进行表达。代表至少四个附加基因的剩余突变体在能力发展期间的稳定期表达β-半乳糖苷酶。我们得出的结论是，com 基因的表达可能是通过转录并以生长阶段特异性的方式进行调节的。这些基因的表达也依赖于能力培养基中的生长，并且与能力发展一样，需要葡萄糖的存在并且依赖于 spo0H 产物。 abrB703 突变部分绕过了对 spo0A 基因产物的依赖性。这些影响在质量上与能力发展的影响相同。后者依赖于 spo0A 和 spo0H，并且 spo0A 依赖性被 abrB703 部分抑制。当在感受态培养基中生长时，一些突变体仍然能够分解成轻和重浮力密度细胞级分。所有这些在轻级分中都更大程度地表达β-半乳糖苷酶，表明这些com基因的表达是细胞类型特异性的。能力的发展并未受到 spo0B、spo0E、spo0F、spo0J 或 sigB（p37 的结构基因）突变的显着影响。
A set of competence (com) mutants of Bacillus subtilis was constructed by using Tn917lacZ as a mutagen. In about half of the mutants, the promoterless lacZ element on the transposon was placed under control of putative com promoters. Expression of the mutant com genes was studed by using the .beta.-galactosidase tag. Two of the mutant genes (those represented by com-124 and com-138) were expressed early in the growth cycle in all of the media tested and were not dependent on the spo0A or spo0H product for expression. The remaining mutants, which represented a minimum of four additional genes, expressed .beta.-galactosidase in stationary phase during the period in which competence developed. We conclude that expression of com genes is probably regulated transcriptionally and in a growth stage-specific manner. Expression of these genes was also dependent on growth in competence medium and, like competence development, required the presence of glucose and was dependent on the spo0H products. The dependence on the spo0A gene product was partially bypassed by the abrB703 mutation. These effects were qualitatively equivalent to those on competence development. The latter was dependent on spo0A and spo0H, and the spo0A dependency was partially suppressed by abrB703. Several of the mutants were still capable of resolution into light and heavy buoyant density cell fractions when grown in competence medium. All of these expressed .beta.-galctosidase to a greater extent in the light fraction, showing that expression of these com genes was cell type specific. Development of competence was not markedly affected by mutations in spo0B, spo0E, spo0F, spo0J, or sigB, the structural gene for p37.