A FUNCTIONAL ORIGIN OF TRANSFER (ORIT) ON THE CONJUGATIVE TRANSPOSON TN916
A FUNCTIONAL ORIGIN OF TRANSFER (ORIT) ON THE CONJUGATIVE TRANSPOSON TN916
复制标题
DOI：
10.1128/jb.177.22.6644-6651.1995
复制
发表时间：
1995-11-01
影响因子：
3.2
通讯作者：
CLEWELL, DB
中科院分区：
文献类型：
--
作者：
JAWORSKI, DD;CLEWELL, DB
18-kb接合转座子Tn 916的转移起点（oriT）已定位于转座子图谱上跨越核苷酸15215至15681的466-bp区域。oriT位于开放阅读框ORF 20和ORF 21之间的顺反子间区域内，该区域包含6组大小为10至20 bp的反向重复序列。该片段包含三个序列，在12 bp的9个中显示出与革兰氏阴性菌中发现的接合质粒的IncP家族的共有切口位点（nic）的同一性。与这些序列之一重叠的是与F质粒的nic位点相似的区域。功能性是基于含有oriT的序列响应于完整染色体携带的转座子Tn 916 Δ E的反式激活而提供涉及穿梭载体pWM 401的嵌合体的顺式作用动员的能力。当选择Tn 916 Δ E时，466或376个核苷酸的克隆片段导致质粒的共转移，其水平约为40%，而110-bp片段导致共转移的频率约为7%。动员是特异性的，因为革兰氏阳性质粒如pAD 1和pAM β 1，以及革兰氏阴性质粒pOX 38（F1和RP 1的衍生物）不动员含oriT的嵌合体。
The origin of transfer (oriT) of the 18-kb conjugative transposon Tn916 has been localized to a 466-bp region which spans nucleotides 15215 to 15681 on the transposon map. The oriT lies within an intercistronic region between open reading frames ORF20 and ORF21 that contains six sets of inverted repeats ranging from 10 to 20 bp in size. The segment contains three sequences showing identity in 9 of 12 bp to the consensus nicking site (nic) of the IncP family of conjugative plasmids found in gram-negative bacteria. Overlapping one of these sequences is a region similar to the nic site of the F plasmid. Functionality was based on the ability of the oriT-containing sequence to provide a cis-acting mobilization of chimeras involving the shuttle vector pWM401 in response to activation in trans by an intact chromosome-borne transposon Tn916 Delta E. Cloned segments of 466 or 376 nucleotides resulted in unselected cotransfer of the plasmid at levels of about 40% when selection was for Tn916 Delta E, whereas a 110-bp segment resulted in cotransfer at a frequency of about 7%. Mobilization was specific in that gram-positive plasmids, such as pAD1 and pAM beta 1, and the gram-negative plasmids pOX38 (a derivative of Fl and RP1 did not mobilize oriT-containing chimeras.