Leaderless transcripts of the crenarchaeal hyperthermophile Pyrobaculum aerophilum
Leaderless transcripts of the crenarchaeal hyperthermophile Pyrobaculum aerophilum
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DOI：
10.1006/jmbi.2001.4669
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发表时间：
2001-06-01
影响因子：
5.6
通讯作者：
Miller, JH
中科院分区：
文献类型：
--
作者：
Slupska, MM;King, AG;Miller, JH
我们通过引物延伸和S-1核酸酶作图，绘制了10个不相关的编码嗜风焦杆菌蛋白基因的转录起始位点。所有的转录本都从计算预测的翻译起始密码子开始，其中两个是由n端蛋白测序支持的。对预测翻译起始密码子周围-50 ~ +50 nt区域的全基因组计算分析显示，一个清晰的上游模式与位于异常靠近翻译起始位置的古细菌TATA盒的一致序列相匹配。基因与最匹配的TATA盒con感觉序列,TATA框之间的距离和翻译开始密码子似乎小于30元。另外两个子元素杰出也发现异常密切的翻译开始密码子:一个转录启动程序元素与C和T频率的重要高程1位置和BRE元素更频繁的在位置基地-29年至-32年(从翻译开始计算网站)。我们还发现其中一个被定位的基因被转录为一个操纵子的第一个基因。对于一组可能位于操纵子内部的基因，通过计算机分析提取的上游信号为与嗜气杆菌16s rRNA互补序列匹配的Shine-Dalgarno模式。综上所述，这些结果表明，在嗜热嗜气芽胞菌中，由单个基因或首先位于操纵子中的基因编码的蛋白质的翻译大部分（如果不是完全）是通过无领导转录本进行的。操纵子中的内部基因可能通过核糖体结合Shine-Dalgarno序列的机制进行翻译。(C) 2001学术出版社。
We mapped transcription start sites for ten unrelated protein-encoding Pyrobaculum aerophilum genes by primer extension and S-1 nuclease mapping. All of the mapped transcripts start at the computationally predicted translation start codons, two of which were supported by N-terminal protein sequencing. A whole genome computational analysis of the regions from -50 to +50 nt around the predicted translation starts codons revealed a clear upstream pattern matching the consensus sequence of the archaeal TATA box located unusually close to the translation starts. For genes with the TATA boxes that best matched the con sensus sequence, the distance between the TATA box and the translation start codon appears to be shorter than 30 nt. Two other promoter elements distinguished were also found unusually close to the translation start codons: a transcription initiator element with significant elevation of C and T frequencies at the -1 position and a BRE element with more frequent A bases at position -29 to -32 (counting from the translation start site). We also show that one of the mapped genes is transcribed as the first gene of an operon. For a set of genes likely to be internal in operons the upstream signal extracted by computer analysis was a Shine-Dalgarno pattern matching the complementary sequence of P. aerophilum 16 S rRNA. Together these results suggest that the translation of proteins encoded by single genes or genes that are first in operons in the hyperthermophilic crenarchaeon P. aerophilum proceeds mostly, if not exclusively, through leaderless transcripts. Internal genes in operons are likely to undergo translation via a mechanism that is facilitated by ribosome binding to the Shine-Dalgarno sequence. (C) 2001 Academic Press.