Tsybul'ko E A, Morozova T V, Filatov D A, Pasiukova E G
Genetika. 2004 Aug;40(8):1058-62.
Expression of the lacZ reporter gene controlled by various deletion derivatives of the regulatory region of the copia retrotransposon was studied in the testes of adult transgenic males of the Drosophila melanogaster y1W67c23(2) strain at the age of 3, 6-9, 12-15, 18-21, and 24-27 days. When the construct contained the full-length regulatory region, which included the 5'-long terminal repeat (LTR) and the 5'-untranslated region (UTR), expression was the lowest in males aged 12-15 days and the highest in males aged 3 or 24-27 days. A similar V-shaped age dependence was previously observed for the copia transposition rate and RNA content in a strain with a high rate of copia transposition. Thus, the V-shaped age dependence of expression, which is unusual for Drosophila, proved to be characteristic of copia regardless of its transposition rate. Deletion of the 5' or 3' end of the LTR, but not of the UTR, changed the age dependence of the level of reporter gene expression. In this case, expression was the highest in 3-day-old males and gradually decreased with age, as typical for many Drosophila genes. It was assumed that the 5'- and 3'-terminal regions of the copia LTR contain regulatory elements responsible for the V-shaped age dependence of expression, while the expression level depends to a greater extent on the regulatory elements of UTR.
在黑腹果蝇y1W67c23(2)品系成年转基因雄性果蝇3、6 - 9、12 - 15、18 - 21和24 - 27日龄的睾丸中，研究了由copia逆转录转座子调控区的各种缺失衍生物控制的lacZ报告基因的表达。当构建体包含全长调控区时，该调控区包括5' - 长末端重复序列（LTR）和5' - 非翻译区（UTR），12 - 15日龄雄性果蝇中的表达最低，3日龄或24 - 27日龄雄性果蝇中的表达最高。先前在copia转座率高的品系中，观察到copia转座率和RNA含量呈现类似的V形年龄依赖性。因此，这种对果蝇来说不寻常的V形表达年龄依赖性，被证明是copia的特征，无论其转座率如何。LTR的5'或3'末端缺失，但UTR缺失则不会改变报告基因表达水平的年龄依赖性。在这种情况下，3日龄雄性果蝇中的表达最高，并随年龄逐渐降低，这是许多果蝇基因的典型情况。据推测，copia LTR的5'和3'末端区域含有负责表达的V形年龄依赖性的调控元件，而表达水平在更大程度上取决于UTR的调控元件。
