Lohe A R, Hartl D L
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge Massachusetts 02138, USA.
Genetics. 1996 May;143(1):365-74. doi: 10.1093/genetics/143.1.365.
An important goal in molecular genetics has been to identify a transposable element that might serve as an efficient transformation vector in diverse species of insects. The transposable element mariner occurs naturally in a wide variety of insects. Although virtually all mariner elements are nonfunctional, the Mos1 element isolated from Drosophila mauritiana is functional. Mos1 was injected into the pole-cell region of embryos of D. virilis, which last shared a common ancestor with D. mauritiana 40 million years ago. Mos1 PCR fragments were detected in several pools of DNA from progeny of injected animals, and backcross lines were established. Because G0 lines were pooled, possibly only one transformation event was actually obtained, yielding a minimum frequency of 4%. Mos1 segregated in a Mendelian fashion, demonstrating chromosomal integration. The copy number increased by spontaneous mobilization. In situ hybridization confirmed multiple polymorphic locations of Mos1. Integration results in a characteristic 2-bp TA duplication. One Mos1 element integrated into a tandem array of 370-bp repeats. Some copies may have integrated into heterochromatin, as evidenced by their ability to support PCR amplification despite absence of a signal in Southern and in situ hybridization.
分子遗传学的一个重要目标是鉴定一种可作为多种昆虫高效转化载体的转座元件。转座元件水手座（mariner）在多种昆虫中自然存在。尽管几乎所有的水手座元件都无功能，但从毛里求斯果蝇（Drosophila mauritiana）中分离出的Mos1元件是有功能的。Mos1被注射到 virilis果蝇胚胎的极细胞区域，virilis果蝇与毛里求斯果蝇在4000万年前有共同祖先。在注射动物后代的几个DNA池中检测到Mos1 PCR片段，并建立了回交品系。由于G0品系是混合的，实际上可能只获得了一次转化事件，产生的最低频率为4%。Mos1以孟德尔方式分离，证明了染色体整合。通过自发转座，拷贝数增加。原位杂交证实了Mos1的多个多态性位置。整合导致特征性的2个碱基对TA重复。一个Mos1元件整合到370个碱基对重复序列的串联阵列中。一些拷贝可能已整合到异染色质中，这可从它们在Southern杂交和原位杂交中无信号但仍能支持PCR扩增的能力得到证明。
