Lohe A R, Hartl D L
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Genetics. 1996 Jul;143(3):1299-306. doi: 10.1093/genetics/143.3.1299.
Germline mobilization of the transposable element mariner is severely inhibited by the insertion of a 4.5- to 11.9-kb fragment of exogenous DNA into a unique SacI site approximately in the middle of the 1286-bp element. In the presence of transposase driven by the germline-specific hsp26-sgs3 promoter, mobilization of the MlwB construct (containing a 11.9-kb insertion) is detected at low frequency. Analysis of a mobilized MlwB element indicated that mobilization is mediated by the mariner transposase. However, transposed MlwB elements are also defective in germline mobilization. Rare, transposase-induced germline excision events were also recovered for such vectors. The estimated rate of excision is < 0.1% per chromosome per generation. Excision appears to be accompanied by gap repair if a suitable template is available. The data imply that the reduced mobility of mariner vectors with exogenous DNA in the SacI site results from disruption of sequences necessary for efficient mobilization. The relative stability may be a valuable property in the uses of mariner-like elements in genetic engineering of insects of economic importance.
转座元件水手号（mariner）的种系动员受到严重抑制，原因是一段4.5至11.9 kb的外源DNA片段插入到了一个独特的SacI位点，该位点大约位于1286 bp元件的中部。在种系特异性热休克蛋白26-衰老相关基因3（hsp26-sgs3）启动子驱动的转座酶存在的情况下，可检测到低频的MlwB构建体（包含11.9 kb插入片段）的动员。对一个动员的MlwB元件的分析表明，动员是由水手号转座酶介导的。然而，转座的MlwB元件在种系动员中也存在缺陷。对于此类载体，也能检测到罕见的、转座酶诱导的种系切除事件。估计每代每条染色体的切除率<0.1%。如果有合适的模板，切除似乎伴随着缺口修复。数据表明，SacI位点带有外源DNA的水手号载体的迁移率降低是由于有效动员所需序列的破坏所致。在对具有经济重要性的昆虫进行基因工程时，这种相对稳定性可能是水手号样元件应用中的一个有价值的特性。
