ACCUMULATION OF BLDA-SPECIFIED TRANSFER-RNA IS TEMPORALLY REGULATED IN STREPTOMYCES-COELICOLOR A3(2)
ACCUMULATION OF BLDA-SPECIFIED TRANSFER-RNA IS TEMPORALLY REGULATED IN STREPTOMYCES-COELICOLOR A3(2)
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DOI：
10.1128/jb.175.7.1995-2005.1993
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发表时间：
1993-04-01
影响因子：
3.2
通讯作者：
CHATER, KF
中科院分区：
文献类型：
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作者：
LESKIW, BK;MAH, R;CHATER, KF
天蓝色链霉菌A3（2）的bldA基因编码稀有UUA密码子的唯一tRNA，该基因的缺失对初生生长没有明显影响，但干扰气生菌丝体的形成和抗生素的产生。为了研究bldA可能的调节作用，鉴定了其转录起始点，并确定了其初级转录物的出现、初级转录物的加工以产生成熟的5'末端以及含有多个UUA密码子的ampC mRNA的表观翻译效率的时间过程。bldA启动子在任何时候都是有活性的，但是初级转录物的5'末端的加工在年轻的培养物中相对低效。这可能涉及反义RNA，启动子探测和体外转录提供了证据。在年轻的文化中，低水平的加工形式的tRNA的存在，然后在较老的文化中增加丰度与观察到的模式不同的，大概是典型的tRNA的积累，这是大约同样丰富的整个生长形成对比。bldA tRNA的5'加工形式的增加的积累与较老培养物中ampC mRNA的更有效翻译相一致，支持以下假设：至少在某些生理条件下，bldA可能对生长后期的事件具有调节影响，例如形态分化和抗生素产生。
Deletion of the bldA gene of Streptomyces coelicolor A3(2), which encodes the only tRNA for the rare UUA codon, had no obvious effects on primary growth but interfered with aerial mycelium formation and antibiotic production. To investigate the possible regulatory role of bldA, its transcription start point was identified, and time courses were determined for the appearance of its primary transcript, the processing of the primary transcript to give a mature 5' end, and the apparent efficiency of translation of ampC mRNA, which contains multiple UUA codons. The bldA promoter was active at all times, but processing of the 5' end of the primary transcript was comparatively inefficient in young cultures. This may perhaps involve an antisense RNA, evidence of which was provided by promoter probing and in vitro transcription. The presence of low levels of the processed form of the tRNA in young cultures followed by increased abundance in older cultures contrasted with the pattern observed for accumulation of a different, presumably typical tRNA which was approximately equally abundant throughout growth. The increased accumulation of the 5' processed form of bldA tRNA coincided with more-efficient translation of ampC mRNA in older cultures, supporting the hypothesis that in at least some physiological conditions, bldA may have a regulatory influence on events late in growth, such as morphological differentiation and antibiotic production.