Luo D, Coen E S, Doyle S, Carpenter R
John Innes Institute, John Innes Centre for Plant Science Research, Norwich, UK.
Plant J. 1991 Jul;1(1):59-69.
New pigmentation mutants were generated by transposon mutagenesis in Antirrhinum majus, in three previously described loci, nivea, delila and incolorata, and two new loci, daphne and olive. The wild-type olive gene is required for the production of dark-green leaves, and the daphne gene for the synthesis of flavones. Five out of the six mutants were both germinally and somatically unstable, indicating that they resulted from transposon insertions. Molecular analysis of the mutant at nivea (niv-600) showed that it was caused by insertion of a new transposon, Tam4. The sequence of Tam4 suggests that it is unable to transpose autonomously and that it is related to Tam1 and Tam2. All three of these transposons have identical inverted repeats, produce 3 bp target duplications, leave similar excision footprints and share at one end a 600-700 bp region containing many palindromic copies of a motif sequence, possibly required in cis for transposition. The somatic excision of Tam4 in niv-600 is at a very low rate compared to germinal excision but it can be activated by crossing to lines carrying derivative alleles of a Tam1 insertion at niv. Molecular analysis of four different pigmentation mutants has shown that insertions of Tam1, Tam2, Tam3 and Tam4 have been obtained, illustrating the potential of general transposon mutagenesis for trapping and isolating new transposons as well as for tagging genes.
通过转座子诱变在金鱼草中产生了新的色素沉着突变体，涉及三个先前描述的位点，即nivea、delila和incolorata，以及两个新位点，daphne和olive。野生型olive基因是深绿色叶片产生所必需的，而daphne基因则参与黄酮类化合物的合成。六个突变体中有五个在生殖和体细胞水平上都不稳定，这表明它们是由转座子插入导致的。对nivea位点（niv - 600）的突变体进行分子分析表明，它是由一个新的转座子Tam4插入引起的。Tam4的序列表明它不能自主转座，并且与Tam1和Tam2相关。所有这三个转座子都具有相同的反向重复序列，产生3 bp的靶标重复，留下相似的切除足迹，并且在一端共享一个600 - 700 bp的区域，该区域包含一个基序序列的许多回文拷贝，可能在转座过程中顺式需要。与生殖切除相比，niv - 600中Tam4的体细胞切除率非常低，但通过与携带niv处Tam1插入的衍生等位基因的品系杂交可以激活它。对四个不同色素沉着突变体的分子分析表明，已获得了Tam1、Tam2、Tam3和Tam4的插入，这说明了通用转座子诱变在捕获和分离新转座子以及标记基因方面的潜力。
