EVIDENCE FOR UNLINKED RRN OPERONS IN THE PLANCTOMYCETE PIRELLULA-MARINA
EVIDENCE FOR UNLINKED RRN OPERONS IN THE PLANCTOMYCETE PIRELLULA-MARINA
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DOI：
10.1128/jb.171.9.5025-5030.1989
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发表时间：
1989-09-01
影响因子：
3.2
通讯作者：
STACKEBRANDT, E
中科院分区：
文献类型：
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作者：
LIESACK, W;STACKEBRANDT, E
对真菌Pirellula marina染色体bamhi酶切DNA的rRNA进行Southern杂交，发现存在两组16S和23S rRNA基因。从λ噬菌体Charon 35文库中分离出两个23S rRNA基因拷贝，分别位于11和13千碱基（kb）的插入片段上。将11kb片段直接克隆到pBR322中，而将约13kb插入片段的5.4 bk BamHI-PstI rDNA亚片段克隆到pUC18中。重组质粒pPI1100和pPI540通过限制性内切酶定位和与大rRNA物种的Southern杂交进行了鉴定。将这两个插入片段亚克隆到噬菌体M13、mp18和mp19中。基因组杂交数据与重组质粒物理特性的相关性表明，与真细菌中rrn操纵子的一般组织结构相比，P. marina的16S rRNA基因与紧密相连的23S-5S rRNA基因分别至少分离了8.5 （pPI540）和4.4 (pPI1100) kb。将两个23S-5S rRNA基因的侧翼区域与已公布的一致结构元件序列进行比较，发现存在假定的转录信号，即单个Pribnow盒、鉴别器、抗终止盒a、B和C，以及一个rho不依赖的终止器。
Southern hybridization of rRNAs to chromosomal BamHI-digested DNA of the eubacterium Pirellula marina revealed the presence of two sets of 16S and 23S rRNA genes. The two copies of the 23S rRNA genes, located on 11- and about 13-kilobase (kb) inserts, were isolated from a lambda bacteriophage Charon 35 library. The 11-kb fragment was cloned directly into pBR322, while a 5.4-bk BamHI-PstI rDNA subfragment of the approximately 13-kb insert was cloned into pUC18. Both recombinant plasmids, pPI1100 and pPI540, were characterized by restriction enzyme mapping and Southern hybridization with the large rRNA species. Restriction fragments from both inserts were subcloned into phage M13 mp18 and mp19. Correlation of genomic hybridization data with physical characterization of recombinant plasmids showed that, in contrast to the general organization of rrn operons in eubacteria, the 16S rRNA genes of P. marina are separated by at least 8.5 (pPI540) and 4.4 (pPI1100) kb, respecitvely, from the closely linked 23S-5S rRNA genes. Comparison of the flanking regions from both 23S-5S rRNA genes with published consensus sequences of structural elements indicates the presence of putative transcription signals, i.e., a single Pribnow box, discriminator, antitermination boxes A, B, and C, and a Rho-independent terminator.