Mutational analysis of a regulatory region in bacteriophage lambda that has overlapping signals for the initiation of transcription and translation.
Mutational analysis of a regulatory region in bacteriophage lambda that has overlapping signals for the initiation of transcription and translation.
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对 lambda 噬菌体中的一个调节区域进行突变分析，该区域具有转录和翻译起始的重叠信号。
DOI：
10.1073/pnas.81.2.555
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发表时间：
1984
影响因子：
11.1
通讯作者：
Rosenberg,M
中科院分区：
文献类型：
--
作者：
Wulff,DL;Mahoney,M;Shatzman,A;Rosenberg,M
噬菌体λ的正调控PRE启动子在结构上与激活PRE转录的调控蛋白（cII）的核糖体结合和NH 2末端编码区重叠。我们已经分离出并表征了发生在36个碱基对重叠区域内的27个不同的点突变。通过DNA序列分析确定的核苷酸分离的遗传交叉数据的比较表明，重组频率在很短的距离被大大抑制。此外，重组频率严重依赖于5个核苷酸或更少距离的交叉区域的精确核苷酸序列。突变定义了精确的位置和序列，这些位置和序列对（i）PRE启动子功能，（ii）cII基因的翻译和（iii）cII基因功能很重要。影响该区域中一个元件功能的突变变化同时定义了其他两个元件的表型沉默改变。启动子功能缺陷的突变（P-RE或cy）聚集在位于PRE mRNA的起始碱基之前约等于10和约等于35个核苷酸的两个区域中，类似于其它启动子中的突变。-10区域中的P-RE突变改变原核启动子中保守的碱基，但-35区域中的P-RE突变不影响其它启动子中通常保守的碱基。cII基因活性缺陷的几个突变影响cII蛋白合成的起始，包括A导致cII编码区外四个碱基的G变化，以及起始密码子中的AUG导致GUG，AUG导致ACG，AUG导致AUA突变。在PRE启动子和cII基因的NH 2-末端区域之间的重叠区域中，cII蛋白中的大多数氨基酸取代不会导致cII功能的丧失，表明该基因的该区域不包含cII功能的必要信息。我们认为，重叠本身是一个进化上保守的结构，它以某种方式协调双向转录和翻译事件发生在这个地区。
The positively regulated PRE promoter of phage lambda structurally overlaps with the ribosome-binding and NH2-terminal coding region of the regulatory protein (cII) that activates PRE transcription. We have isolated and characterized 27 different point mutations that occur within the 36-base-pair overlapping region. A comparison of genetic crossover data with nucleotide separations as determined by DNA sequence analysis reveals that recombination frequencies are greatly depressed at very short distances. Moreover, recombination frequency is critically dependent upon the precise nucleotide sequence of the crossover region for distances of five nucleotides or less. The mutations define precise positions and sequences that are important to (i) PRE promoter function, (ii) translation of the cII gene, and (iii) cII gene function. Mutational changes that affect the function of one element in this region concomitantly define phenotypically silent alterations in the other two elements. Mutations deficient in promoter function (P-RE or cy) are clustered in two regions that lie approximately equal to 10 and approximately equal to 35 nucleotides before the initial base of PRE mRNA, analogous to mutations in other promoters. P-RE mutations in the -10 region alter bases that are conserved in prokaryotic promoters, but P-RE mutations in the -35 region do not affect bases that are normally conserved in other promoters. Several mutations deficient in cII gene activity affect the initiation of cII protein synthesis, including an A leads to G change four bases outside the cII coding region, and AUG leads to GUG, AUG leads to ACG, and AUG leads to AUA mutations in the initiation codon. In the region of overlap between the PRE promoter and the NH2-terminal region of the cII gene, most amino acid substitutions in the cII protein do not result in a loss of cII function, indicating that this region of the gene does not contain essential information for cII function. We suggest that the overlap itself is an evolutionarily conserved structure and that it somehow coordinates the bidirectional transcriptional and translational events that occur in this region.