Hoshino A, Inagaki Y, Iida S
Department of Biological Science and Technology, Science University of Tokyo, Chiba, Japan.
Mol Gen Genet. 1995 Apr 10;247(1):114-7. doi: 10.1007/BF00425828.
The 6.4 kb transposable element Tpn1 belonging to the En/Spm family was found within one of the DFR (dihydroflavonol-4-reductase) genes for anthocyanin biosynthesis in a line of Japanese morning glory (Pharbitis nil) bearing variegated flowers. Sequencing of the Tpn1 element revealed that it is 6412 bp long and carries 28-bp perfect terminal inverted repeats. Its subterminal repetitive regions, believed to be the cis-acting sequences for transposition, show striking structural features. Twenty-two copies of the 10-bp sequence motif GACAACGGTT can be found as direct or inverted repeats within 650 bp of the 5' end of the element, and 33 copies of the sequence motif lie within 800 bp of the 3' terminus. All these 22 copies of the sequence motif near the 5' terminus and 30 copies in the 3' terminal region are arranged as inverted repeats and 3-8 bp AT-rich sequences are detected between these inverted repeats. In addition, four copies of 122-bp tandem repeats and six copies of 104-bp tandem repeats are present in the 5' and 3' subterminal repetitive regions, respectively. No large open reading frame characteristic of autonomous elements of the En/Spm family can be detected within the element. The results are discussed with respect to heritable changes in flower variegation in this line of Japanese morning glory.
在一株开杂色花的日本牵牛（ Pharbitis nil ）中，属于 En/Spm 家族的 6.4 kb 转座元件 Tpn1 被发现存在于花青素生物合成的一个二氢黄酮醇 -4- 还原酶（ DFR ）基因内。对 Tpn1 元件的测序显示，它长 6412 bp ，带有 28 bp 的完美末端反向重复序列。其亚末端重复区域被认为是转座的顺式作用序列，呈现出显著的结构特征。在该元件 5' 端 650 bp 范围内可发现 22 个拷贝的 10 bp 序列基序 GACAACGGTT 呈正向或反向重复，在 3' 末端 800 bp 范围内有 33 个该序列基序的拷贝。 5' 末端附近的所有这 22 个序列基序拷贝以及 3' 末端区域的 30 个拷贝均以反向重复排列，并且在这些反向重复之间检测到 3 - 8 bp 的富含 AT 的序列。此外，在 5' 和 3' 亚末端重复区域分别存在 4 个拷贝的 122 bp 串联重复序列和 6 个拷贝的 104 bp 串联重复序列。在该元件内未检测到 En/Spm 家族自主元件特有的大开放阅读框。针对这株日本牵牛中花杂色的可遗传变化对结果进行了讨论。
