Coen E S, Carpenter R
AFRC, Institute of Plant Science Research, John Innes Institute, Norwich, UK.
EMBO J. 1988 Apr;7(4):877-83. doi: 10.1002/j.1460-2075.1988.tb02891.x.
Niv-525 is a semi-dominant allele of the nivea locus, which encodes the enzyme chalcone synthase required for flower pigment biosynthesis in Antirrhinum majus. Plants heterozygous for niv-525 and wild-type (Niv+) allele, have flowers with a reduced intensity and novel spatial pattern of pigmentation compared with Niv+ homozygotes. In heterozygotes, niv-525 acts in trans to reduce the steady-state level of nivea transcript produced by its Niv+ homologue and hence the quantity of chalcone synthase protein. Niv-525 carries an inverted duplication of 207 bp in its promoter region which has arisen following excision of the transposable element Tam 3. This structure can be explained by a model of plant transposable element excision that involves resolution of two hairpin DNA molecules. Possible mechanisms for the trans-acting effect of niv-525 and its relationship to other examples of allelic interactions, such as transvection in Drosophila melanogaster, are discussed.
Niv-525是nivea基因座的一个半显性等位基因，该基因座编码金鱼草中花色素生物合成所需的查尔酮合酶。与Niv+纯合子相比，niv-525和野生型（Niv+）等位基因的杂合植物的花朵色素沉着强度降低且呈现新的空间模式。在杂合子中，niv-525通过反式作用降低其Niv+同源物产生的nivea转录本的稳态水平，从而减少查尔酮合酶蛋白的数量。Niv-525在其启动子区域携带一个207 bp的反向重复序列，该序列是在转座元件Tam 3切除后出现的。这种结构可以用一种涉及两个发夹DNA分子解析的植物转座元件切除模型来解释。本文讨论了niv-525反式作用的可能机制及其与其他等位基因相互作用实例（如黑腹果蝇中的转座效应）的关系。
