Hoffman-Liebermann B, Liebermann D, Kedes L H, Cohen S N
Mol Cell Biol. 1985 May;5(5):991-1001. doi: 10.1128/mcb.5.5.991-1001.1985.
We describe here a family of foldback transposons found in the genome of the higher eucaryote, the sea urchin Strongylocentrotus purpuratus. Two major classes of TU elements have been identified by analysis of genomic DNA and TU element clones. One class consists of largely similar elements with long terminal inverted repeats (IVRs) containing outer and inner domains and sharing a common middle segment that can undergo deletions. Some of these elements contain insertions. The second class is highly heterogeneous, with many different middle segments nonhomologous to those of the first-class and variable-sized inverted repeats that contain only an outer domain. The middle and insertion segments of both classes carry sequences that also are found unassociated from the inverted repeats at many other genomic locations. We conclude that the TU elements are modular structures composed of inverted repeats plus other sequence domains that are themselves members of different families of dispersed repetitive sequences. Such modular elements may have a role in the dispersion and rearrangement of genomic DNA segments.
我们在此描述了在高等真核生物紫海胆（Strongylocentrotus purpuratus）基因组中发现的一个回文转座子家族。通过对基因组DNA和转座子元件克隆的分析，已鉴定出两类主要的TU元件。一类主要由具有长末端反向重复序列（IVRs）的相似元件组成，这些重复序列包含外部和内部结构域，并共享一个可发生缺失的共同中间片段。其中一些元件含有插入序列。第二类高度异质，有许多不同的中间片段与第一类的中间片段非同源，且其反向重复序列大小可变，仅包含一个外部结构域。两类元件的中间和插入片段所携带的序列，在许多其他基因组位置也能在与反向重复序列不相关的情况下被发现。我们得出结论，TU元件是由反向重复序列加上其他序列结构域组成的模块化结构，而这些序列结构域本身就是不同家族的分散重复序列的成员。这类模块化元件可能在基因组DNA片段的分散和重排中发挥作用。
