Liu D, Crawford N M
Department of Biology and Center for Molecular Genetics, University of California at San Diego, La Jolla 92093, USA.
Genetics. 1998 Jan;148(1):445-56. doi: 10.1093/genetics/148.1.445.
Tag1 is an autonomous transposon of Arabidopsis thaliana. The excision behavior of Tag1 during reproductive and vegetative development was examined using CaMV 35STag1-GUS constructs. Germinal reversion frequencies varied from 0 to 27% and correlated with Tag1 copy number. Southern blot and somatic sector analyses indicated that each revertant was derived from an independent excision event, and approximately 75% of the revertants had new Tag1 insertions. Revertants were obtained with similar frequencies from the male and female parents. In flowers, small somatic sectors were observed in siliques, carpels, petals and sepals while stemlike organs (filaments and pedicels) had larger sectors. No sectors encompassing entire flowers or inflorescences were observed, however, indicating that excision occurs late in flower development and rarely in inflorescence meristems. Late excision was also observed during vegetative development with 99.8% of leaves showing small sectors encompassing no more than 20 cells. Roots and cotyledons, however, showed larger sectors that included entire lateral roots and cotyledons. These results indicate that Tag1 can excise in the embryo and all the organs of the plant with the timing of excision being restricted to late stages of vegetative and reproductive development in the shoot.
Tag1是拟南芥中的一种自主转座子。利用CaMV 35S-Tag1-GUS构建体研究了Tag1在生殖和营养发育过程中的切除行为。生殖细胞回复突变频率在0%至27%之间变化，并与Tag1拷贝数相关。Southern杂交和体细胞扇形分析表明，每个回复突变体均来自独立的切除事件，约75%的回复突变体有新的Tag1插入。从雄性和雌性亲本获得回复突变体的频率相似。在花中，在角果、心皮、花瓣和萼片中观察到小的体细胞扇形，而茎状器官（花丝和花梗）有较大的扇形。然而，未观察到涵盖整个花或花序的扇形，这表明切除发生在花发育后期，在花序分生组织中很少发生。在营养发育过程中也观察到后期切除，99.8%的叶片显示小扇形，包含不超过20个细胞。然而，根和子叶显示出较大的扇形，包括整个侧根和子叶。这些结果表明，Tag1可以在胚胎和植物的所有器官中切除，切除时间仅限于地上部分营养和生殖发育的后期。
