Lin N T, Tseng Y H
Institute of Molecular Biology and Department of Botany, National Chung Hsing University, Taichung, Taiwan, Republic of China.
Biochem Biophys Res Commun. 1997 Jun 18;235(2):276-80. doi: 10.1006/bbrc.1997.6776.
A 6.7-kb Sau3A1 fragment containing ribosomal RNA genes was cloned from the chromosome of Xanthomonas campestris pv. campestris strain 17 by a PCR-based strategy. Nucleotide sequence was determined for the 16S rRNA gene (1,544 nt). This gene has a G+C content of 54.9% which is similar to the 16S rRNA genes of Escherichia coli and Pseudomonas aeruginosa but different from the value reported for the whole X. campestris chromosome (64%). Sequence alignment revealed that AGGAGG is consensus for ribosome binding, with the internal GGAG to be paired most frequently with the anti-Shine-Dalgarno sequence. This consensus sequence was found in the regions upstream from the initiation codon of 98 Xanthomonas genes among 116 aligned, but not in the remaining genes. This suggests that about 16% of the Xanthomonas genes do not possess typical ribosome binding sites and another mechanism may be required for recognition of correct translation initiation sites. Two rrn operons were detected in Xc17 chromosome by pulsed-field gel electrophoresis and Southern hybridization.
通过基于PCR的策略，从野油菜黄单胞菌野油菜致病变种17菌株的染色体中克隆出一个含有核糖体RNA基因的6.7 kb Sau3A1片段。测定了16S rRNA基因（1544 nt）的核苷酸序列。该基因的G+C含量为54.9%，这与大肠杆菌和铜绿假单胞菌的16S rRNA基因相似，但与报道的整个野油菜黄单胞菌染色体的值（64%）不同。序列比对显示，AGGAGG是核糖体结合的共有序列，内部的GGAG最常与反Shine-Dalgarno序列配对。在116个比对的野油菜黄单胞菌基因中，98个基因起始密码子上游区域发现了该共有序列，其余基因中未发现。这表明约16%的野油菜黄单胞菌基因不具有典型的核糖体结合位点，可能需要另一种机制来识别正确的翻译起始位点。通过脉冲场凝胶电泳和Southern杂交在Xc17染色体中检测到两个rrn操纵子。
