van Houwelingen A, Souer E, Spelt K, Kloos D, Mol J, Koes R
Department of Genetics, Vrije Universiteit, BioCentrum Amsterdam, The Netherlands.
Plant J. 1998 Jan;13(1):39-50. doi: 10.1046/j.1365-313x.1998.00005.x.
Fifty new flower pigmentation mutants in Petunia hybrida using endogenous transposable elements (TEs) as a mutagen were generated. Forty-six mutants displayed somatic and sporogenic instability indicating that they were caused by a TE. Phenotypic analysis showed that the mutation altered either anthocyanin biosynthesis (40 alleles for seven loci), the intracellular pH of petals (six alleles for three loci) or the shape of petal cells (two alleles for two loci). To identify the TEs responsible for the mutations, the authors subjected 16 alleles of the anthocyanin-3 (an3) locus, encoding flavanone 3 beta-hydroxylase, to molecular analysis. This showed that 11 out of 12 unstable an3 alleles harboured TE insertions of a single family, dTph1, while one allele harboured a new 177 bp TE designated dTph2. In addition, the authors found one an3 allele (an3-W138A) in which a dTph1 element had inserted 30 bp upstream the translation start, without inactivating the gene. This 'cryptic' element was responsible for the creation of a stable recessive (untagged) an3 allele, where a large rearrangement inactivated the gene. These findings indicate that mutants for novel loci are most likely tagged by dTph1 elements opening the way for their isolation.
利用内源性转座元件（TEs）作为诱变剂，在矮牵牛中产生了50个新的花色突变体。46个突变体表现出体细胞和孢子发生不稳定性，表明它们是由TE引起的。表型分析表明，突变改变了花青素生物合成（7个位点的40个等位基因）、花瓣的细胞内pH值（3个位点的6个等位基因）或花瓣细胞的形状（2个位点的2个等位基因）。为了鉴定导致突变的TEs，作者对编码黄烷酮3β-羟化酶的花青素-3（an3）位点的16个等位基因进行了分子分析。结果表明，12个不稳定的an3等位基因中有11个含有单个家族dTph1的TE插入，而一个等位基因含有一个新的177 bp的TE，命名为dTph2。此外，作者发现一个an3等位基因（an3-W138A），其中一个dTph1元件插入到翻译起始位点上游30 bp处，而没有使基因失活。这个“隐蔽”元件导致了一个稳定的隐性（无标签）an3等位基因的产生，在这个等位基因中，一个大的重排使基因失活。这些发现表明，新位点的突变体很可能被dTph1元件标记，为它们的分离开辟了道路。
