Retrotransposons of rice involved in mutations induced by tissue culture
Retrotransposons of rice involved in mutations induced by tissue culture
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DOI：
10.1073/pnas.93.15.7783
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发表时间：
1996-07-23
影响因子：
11.1
通讯作者：
Kanda, M
中科院分区：
文献类型：
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作者：
Hirochika, H;Sugimoto, K;Kanda, M
水稻反转录转座子家族（Tos 1-Tos 5）已有报道。本文报道了15个新的水稻反转录转座子家族（Tos 6-Tos 20）。与酵母和果蝇的反转录转座子相反，所有的水稻反转录转座子在正常生长条件下都表现出无活性（或几乎无活性）。水稻反转录转座子中的三个（Tos 10、Tos 17和Tos 19）在组织培养条件下被激活。对其中活性最高的Tos 17进行了详细的研究。随着培养时间的延长，Tos 17基因拷贝数增加。在从组织培养物再生的所有植物中，包括转基因植物，检测到5至30个转座Tos 17拷贝。Tos 17的转录本仅在组织培养条件下检测到，表明Tos 17的转座主要在转录水平上调控。为了检查Tos 17转座的靶位点特异性，分析了转座的Tos 17拷贝侧翼的序列。在检查的八个靶位点中至少有四个是编码区。其他靶位点也可能在基因中，因为四分之二被转录。对光敏色素A基因和S-受体激酶相关基因Tos 17-插入的再生植株进行了鉴定。这些结果表明，Tos 17的激活是组织培养诱导突变的重要原因。组织培养诱导Tos 17的激活可能是一个有用的工具，插入突变和基因的功能分析。
Five retrotransposon families of rice (Tos1-Tos5) have been reported previously. Here we report 15 new retrotransposon families of rice (Tos6-Tos20). In contrast to yeast and Drosophila retrotransposons, all of the rice retrotransposons examined appear inactive (or almost inactive) under normal growth conditions. Three of the rice retrotransposons (Tos10, Tos17, and Tos19) are activated under tissue culture conditions. The most active one, Tos17, was studied in detail. The copy number of Tos17 increased with prolonged culture period. In all of the plants regenerated from tissue cultures, including transgenic plants, 5 to 30 transposed Tos17 copies were detected. The transcript of Tos17 was only detected under tissue culture conditions, indicating that the transposition of Tos17 is mainly regulated at the transcriptional level. To examine the target-site specificity of Tos17 transposition, sequences flanking transposed Tos17 copies were analyzed. At least four out of eight target sites examined are coding regions. Other target sites may also be in genes because two out of four were transcribed. The regenerated plants with Tos17-insertions in the phytochrome A gene and the S-receptor kinase-related gene were identified. These results indicate that activation of Tos17 is an important cause of tissue culture-induced mutations. Tissue culture-induced activation of Tos17 may be a useful tool for insertional mutagenesis and functional analysis of genes.