Reduced Germline Mobility of a mariner Vector Containing Exogenous DNA: Effect of Size or Site?

[摘要] 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 Sac I site approximately in the middle of the 1286bp 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 marinertransposase. 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 Sac I 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.

[学科分类] 医学（综合）