昆虫遗传转化品系的常用标记

遗传转化标记是将遗传修饰昆虫从野生型种群中分辨出来的根据,遗传转化昆虫的鉴定、转化品系的维持及其遗传稳定性的监测都依赖于可靠的标记系统,发展易于应用和监测的转化标记能够极大地促进害虫遗传防治的相关研究。用于遗传修饰昆虫的转化标记主要有昆虫眼睛颜色标记基因、抗药性标记基因和荧光蛋白标记基因等。非果蝇类昆虫首个遗传转化品系的鉴定是通过眼睛颜色突变而实现,但大多数昆虫物种没有可用的突变体或缺少相应基因的信息,从而限制了眼睛颜色标记的应用。抗药性基因标记虽然能够通过对转化昆虫进行集体选择而大幅度提高筛选转化体的效率,但由于其鉴定的准确性不高且存在安全性问题,未得到广泛应用。荧光蛋白标记基因的发展则显著拓宽了能够转化的昆虫种类。从水母分离的绿色荧光蛋白(GFP)经突变方法获得了多种不同荧光性质的突变体,经人为修饰后与适宜的强启动子构成转化标记载体,能够有效鉴定更多昆虫物种的遗传转化个体,其中应用较多的是增强型绿色荧光蛋白(EGFP)。此外,从珊瑚属海葵中分离得到的红色DsRed标记基因提供了多样化的红色荧光蛋白选择,在某些生物中DsRed与GFP联合应用的表现明显优于GFP突变体,所以其应用前景也非常广泛。本文着重从眼睛颜色、抗药性和荧光蛋白等3个方面阐述了标记基因的发展历史与现状,并对其今后的发展方向进行了展望。

Commonly used transformation markers in genetically modified insects

Transformation markers offer a tool to distinguish the genetically modified insects from wild types. Both the identification of transformants and the maintenance of transformed lines depend on reliable transformation makers. In addition, the evaluation of the genetic stability of released genetically modified insects needs strong and stable markers. Thus the development of broadly applicable, easily detectable and reliable transformation markers will facilitate the study of genetic pest management. In general, eye color genes, drug resistance genes and fluorescent protein genes can be used as markers in genetically modified insects. The first efficient identification of a non-drosophilid insect transformation line was based on the rescue of eye color mutant phenotypes. However, for most insect species, the application of eye color markers is limited because of the lack of suitable recipient mutant strains and less information on related genes. Markers based on drug resistance genes can improve the screening efficiency of transformants, but the selection for drug resistance is problematic and prone to have false positives or negatives with potential biosecurity problems. Fluorescent protein gene markers significantly facilitate the development of stable insect transformation lines. The green fluorescent protein (GFP, isolated from the jellyfish Aequorea victoria) and its variants with various fluorescent characteristics can be combined with suitable, strong promoters to serve as transformation markers for a wide range of insect species and guarantee the reliable screening of the transformants. In this category, the enhanced green fluorescent protein (EGFP) was mostly used. Besides, the red fluorescent protein (DsRed), isolated from the mushroom coral, Discosoma striata, provides a selection of red fluorescent proteins with better performance than GFP mutants. This paper reviews the history and status of transformation markers including eye color genes, drug resistance genes and the fluorescent protein genes. The potential roles of transformation markers in genetic pest management are also discussed.