Cram D S, Loh S M, Cheah K C, Skurray R A
Department of Microbiology, Monash University, Clayton, Victoria, Australia.
Gene. 1991 Jul 31;104(1):85-90. doi: 10.1016/0378-1119(91)90469-r.
The nucleotide sequence of the region downstream of transfer gene traI, including fertility inhibition gene finO, on the conjugative plasmids F and R6-5, has been determined. Analysis of the F sequence revealed two open reading frames (ORF's), ORF248 and ORF186; ORF186 (finO) is interrupted by the insertion of IS3. The R6-5 sequence also contained ORF248 and an intact ORF186, although an additional ORF (ORF286) was located between the two genes. ORF248, which we have designated traX, and ORF186 (finO) are highly conserved on both plasmids. The organisation of these genes indicates that traI and traX on F, and traI, traX and ORF286 on R6-5 are co-transcribed from their respective promoters upstream of traI. Sequences homologous to traX were detected on a range of conjugative F-like plasmids, whereas sequences homologous to ORF286 were only found on plasmids R6-5, R100 and R1. The conservation of traX sequences suggests a functional importance for that gene and/or its product.
已确定接合质粒F和R6 - 5上转移基因traI下游区域的核苷酸序列，包括育性抑制基因finO。对F序列的分析揭示了两个开放阅读框（ORF），即ORF248和ORF186；ORF186（finO）因IS3的插入而中断。R6 - 5序列也包含ORF248和完整的ORF186，尽管在这两个基因之间还有一个额外的ORF（ORF286）。我们命名为traX的ORF248和ORF186（finO）在这两种质粒上都高度保守。这些基因的组织方式表明，F质粒上的traI和traX以及R6 - 5质粒上的traI、traX和ORF286是从traI上游各自的启动子共同转录的。在一系列接合性F样质粒上检测到了与traX同源的序列，而仅在质粒R6 - 5、R100和R1上发现了与ORF286同源的序列。traX序列的保守性表明该基因和/或其产物具有功能重要性。
