Capture of transposons utilizing mutable chlorophyll mutant in rice and tomato

为了在高等植物中分离出一个新的转座子，我们进行了抗羟脯氨酸(一种脯氨酸类似物)突变体的筛选，因为一些对氨基酸类似物具有抗性的突变体受到奇怪的遗传行为的控制。然而，通过这项研究，没有获得转座元件的证据。(长谷川)：与大多数其他剪切和粘贴型转座子不同，TAM3在金鱼草中的转座频率受到温度的严格控制：TAM3在25℃时很少转座，但在15℃时转座频率更高。我们发现温度变化引起了Tam3末端区域甲基化状态的显著变化：较高的温度导致超甲基化，而较低的温度导致较低的甲基化(Kishima)。为了寻找Lyt家族的新成员，我们对来自番茄的1.3 kb转座子样元件Lyt1的TIR序列进行了特异的PCR。在扩增产物中，有一个片段在相应的…序列中插入了2.7kb对Lyt1的更多响应和包含该序列的可能的Lyt元件被称为Lyt2。经Southern杂交分析(Ogura和Masuda)，番茄基因组中Lyt2相关序列的拷贝数约为20个。从水稻品种Gimbozu中诱导的一个隐性突变基因slg可能受一个新发现的转座子(Sairyu，在日语中的意思是细长颖)控制，我们认为slg是由于Sairyu的插入而失活的Rurm1，slg的反向突变归因于Sairyu(Okumoto)的缺失导致Rurm1的重新激活。VAR2基因的克隆和分子鉴定表明，它可能编码FtsH的叶绿体同源物，FtsH是一种依赖于ATP的金属蛋白酶，属于参与多种细胞功能的一个大蛋白家族(Sakamoto)。以稳定的叶绿素突变体为材料，用碳离子束辐照诱变了一个突变体。诱变突变体的这种突变性是遗传的，这表明隐蔽的沉默转座子可能被离子束照射重新激活(前川和田中)。较少

For isolating a new transposon in higher plants, the selection of mutants resistant to hydroxyproline (a proline analog) was conducted, because some mutants resistant to an amino acid analog have been controlled by curious genetic behavior. However, through the study no evidence for transposable elements was obtained. (Hasegawa).Unlike most other cut-and-paste type transposons, the transposition frequency of Tam3 in Antirrhinum is tightly controlled by temperature : Tam3 transposes rarely at 25 ℃, but much more frequently at 15 ℃. We found that temperature shift induced a remarkable change of the methylation state of the Tam3 end regions : higher temperature resulted in hyper-methylation, while lower temperature resulted in reduced methylation (kishima).We carried out PCR with primers specific to the TIRs of a 1.3-kb transposon-like element Lyt1 from tomato to search for new members of the Lyt family. Among the amplified products, one fragment had a 2.7-kb insertion in a sequence corre … More sponding to Lyt1 and the putative Lyt element containing this sequence was termed Lyt2. The copy number of Lyt2-related sequences in the tomato genome was estimated to be approximately 20 by Southern blot analysis (Ogura and Masuda).The mutable slender glume gene (slg), a recessive mutant gene induced from rice variety Gimbozu, was assumed to be controlled by a newly found transposon (named Sairyu, meaning slender glume in Japanese) belongs to MITEs family in rice, we suggest that slg is inactivated Rurm1 due to the insertion of Sairyu and that reverse mutation of slg is ascribed to the reactivation of Rurm1 caused by the deletion of Sairyu (Okumoto).An Arabidopsis variegated mutant was isolated by T-DNA tagging. Cloning and molecular characterization of the VAR2 locus revealed that it potentially encodes a chloroplastic homologue of FtsH, an ATP-dependent metalloprotease that belongs to a large protein family involved in various cellular functions (Sakamoto). A mutable chlorophyll mutant was induced from stable chlorophyll mutants by carbon ion beam irradiation. This mutability of the induced mutant was inherited, suggesting that cryptic silent transposon might be reactivated by ion beam irradiation (Maekawa and Tanaka). Less