Genome rearrangements and gene regulation in higher plants

开蓝色花的日本牵牛花(Lpomoea Nil)具有广泛的遗传和生理研究历史。目前已分离出一些与花色相关的自发突变体，一些证据表明与EN/SPM相关的转座元件TPN 1及其近缘是这些自发突变的主要来源。事实上，许多花色突变包括白花突变都是由TPN 1相关的非自主元件整合引起的。其中之一是紫色可变等位基因，赋予带有蓝色斑点和扇形的紫色花。紫色基因编码液泡型Na~+/H~+交换器，负责提高液泡中蓝色花色的pH值。普通牵牛花(Ipomoea Purpurea)的可变片状品系表现为白色的片状花朵，片状突变是通过将转座元件Tip 100插入到CHS-D基因中以合成花青素而引起的。3.9kb的Tip 100元件属于ACID家族。我们研究了Tip 100是否是一个能够在异源烟草中转座的自主元件。完整的Tip 100元件能够从其在导入载体中的原始位置切除并重新插入到烟草基因组中的新位置，而其内部缺失衍生物不能。根据这些结果，我们得出结论：Tip 100是一个自主元件，通过同源重组修饰靶染色体基因是研究基因功能的一种强有力的反向遗传学工具。我们正试图开发一种通过在水稻单基因蜡质中进行同源重组来定向基因破坏的方法。分离出一株转基因水稻植株，其目的基因被转基因基因破坏，这似乎是一个杂合子，其基因组中只有一个整合的转基因拷贝。

The Japanese morning glory (lpomoea nil) displaying blue flowers has an extensive history of genetic and physiological studies. A number of its spontaneous mutants related to the flower colors have been isolated, and several lines of evidence indicate that an En/Spm-related transposable element Tpn 1 and its relatives are major sources of these spontaneous mutations. Indeed, many flower color mutants including white flower mutants are caused by integration of Tpn 1-related non-autonomous elements. One of them is a purple-mutable allele conferring purple flowers with blue spots and sectors. The purple gene was identified to encode a vacuolar Na^+/H^+ exchanger that is responsible for increase vacuolar pH for blue flower coloration.The mutable flaked line of the common morning glory (Ipomoea purpurea) displays white flowers with colored flakes, and the flaked mutation is caused by the insertion of a transposable element Tip 100 into the CHS-D gene for anthocyanin biosynthesis. The 3.9 kb Tip 100 element belongs to the AciDs family. We examined whether Tip 100 is an autonOmous element capable of transposition in heterologous tobacco plants. The intact Tip 100 element was able to excise from its original position in an introduced vector and to reinsert into new sites in the tobacco genome, whereas its internal deletion derivative was not. Based on these results, we concluded that Tip 100 is an autonomous element.The modification of targeted chromosomal genes through homologous recombination is a powerful tool of reverse genetics for characterizing gene functions. We are trying to develop a procedure for targeted gene disruption by homologous recombination in the single locus gene Waxy of rice. A transgenic rice plant having a targeted gene disrupted by a transgene was isolated, which appears to be a heterozygote with only one copy of the integrated transgene in its genome.