Science. 1986 Oct 10;234(4773):210-1. doi: 10.1126/science.234.4773.210.
The self-mobile maize transposable element Ac (Activator) displays two trans-acting genetic functions: it induces transposition of the element Ds (Dissociation) but, as its dosage is increased, it also inhibits transposition. Previous work has shown that the 4563 base pair (bp)-long Ac element contains three open reading frames (ORF's) and that a deletion in ORF 1 in wx-m9(Ds), a Ds derivative from Ac isolated at the wx (waxy) locus, results in loss of transposition. The Ds element in the bronze allele bz-m2(DI) is shown to have arisen from Ac by a 1312-bp deletion that is located almost entirely within ORF 2 and does not affect ORF 1. The Ds elements in wx-m9(Ds) and bzm2(DI), defective in ORF 1 and ORF 2, respectively, do not complement genetically to restore the transposition function of Ac; therefore, this function must be specified jointly by ORF's 1 and 2. Furthermore, since bz-m2(DI) does not contribute to Ac's inhibitory dosage effect, both Ac properties result from the expression of the same genetic functional unit.
自主移动的玉米转座因子 Ac（激活子）表现出两种反式作用的遗传功能：它诱导元件 Ds（解离）的转座，但随着其剂量的增加，它也抑制转座。以前的工作表明，长 4563 个碱基对（bp）的 Ac 元件包含三个开放阅读框（ORF），并且在 wx-m9(Ds)中 ORF1 的缺失，wx-m9(Ds)是从 Ac 分离出来的一个 Ds 衍生物，位于 wx（蜡质）基因座，导致转座丧失。在青铜等位基因 bz-m2(DI)中，Ds 元件显示由 Ac 通过 1312-bp 的缺失而产生，该缺失几乎完全位于 ORF2 内，不影响 ORF1。在 wx-m9(Ds)和 bz-m2(DI)中的 Ds 元件分别在 ORF1 和 ORF2 中缺失，在遗传上不能互补以恢复 Ac 的转座功能；因此，这个功能必须由 ORF1 和 ORF2 共同指定。此外，由于 bz-m2(DI)不能促进 Ac 的抑制剂量效应，因此 Ac 的这两种特性都源于相同遗传功能单位的表达。
