Girjes A A, Carrick F N, Lavin M F
Queensland Cancer Fund Research Unit, Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia.
Res Microbiol. 1997 Jun;148(5):413-25. doi: 10.1016/S0923-2508(97)83872-7.
We showed in 1988 that there are two strains of Chlamydia psittaci which infect the koala (Phascolarctos cinereus). In order to further investigate the role of these chlamydial strains in pathogenesis, we have attempted to identify genes of koala type I strain chlamydia which are involved in the immunogenic response. Transformation of Escherichia coli with a plasmid containing a 6.3-kb fragment (pKOC-10) of C. psittaci DNA caused the appearance of a specific chlamydial lipopolysaccharide (LPS) epitope on the host strain. The smallest DNA fragment capable of inducing the expression of chlamydial LPS was an XbaI fragment, 2.4 kb in size (pKOC-5). DNA sequence analysis of the complete fragment revealed regions of high identity, at the amino acid level, to the gseA genes of C. pneumoniae, C. psittaci 6BC and C. trachomatis, and the kdtA gene of E. coli which code for transferases catalysing the addition of 3-deoxy-D-manno-octulosonic acid (Kdo) residues to lipid A. Two open reading frames (ORFs) of 1,314 and 501 nucleotides in size, within the 2.4-kb fragment, were evident, and mRNA species corresponding to these ORFs were detected by Northern analysis. Both ORF1 and ORF2 are required for the appearance of chlamydia-specific LPS on the surface of recombinant E. coli.
1988年我们发现有两种鹦鹉热衣原体菌株可感染考拉（树袋熊）。为了进一步研究这些衣原体菌株在发病机制中的作用，我们试图鉴定考拉I型衣原体菌株中参与免疫应答的基因。用含有鹦鹉热衣原体DNA的6.3 kb片段（pKOC - 10）的质粒转化大肠杆菌，导致宿主菌株表面出现特定的衣原体脂多糖（LPS）表位。能够诱导衣原体LPS表达的最小DNA片段是一个大小为2.4 kb的XbaI片段（pKOC - 5）。对完整片段的DNA序列分析显示，在氨基酸水平上，与肺炎衣原体、鹦鹉热衣原体6BC和沙眼衣原体的gseA基因以及大肠杆菌的kdtA基因具有高度同源性，这些基因编码催化将3 - 脱氧 - D - 甘露糖辛酮酸（Kdo）残基添加到脂质A上的转移酶。在2.4 kb片段内有两个大小分别为1314和501个核苷酸的开放阅读框（ORF），通过Northern分析检测到了与这些ORF对应的mRNA种类。重组大肠杆菌表面出现衣原体特异性LPS需要ORF1和ORF2两者。
