Okada N, Hamada M
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
J Mol Evol. 1997;44 Suppl 1:S52-6. doi: 10.1007/pl00000058.
Our group demonstrated recently that the 3' ends of several families of tRNA-derived SINEs (short interspersed repetitive elements) originated from the 3' ends of LINEs (long interspersed repetitive elements) [Ohshima et al. (1996) Mol. Cell. Biol. 16:3756-3764]. Two fully characterized examples of such organization were provided by the tortoise Pol III/SINE and the salmonid HpaI family of SINEs, and two probable examples were provided by the tobacco TS family of SINEs and the salmon SmaI family of SINEs. This organization of SINEs can explain their potential to retropose in the genome since it appears reasonable that the sites for recognition of LINEs by reverse transcriptase should be located within the 3'-end sequences of LINEs. We now add another example to this category of SINEs. In the bovine genome, there are Bov-tA SINEs, which belong to the superfamily of tRNA-derived families of SINEs, and Bov-B LINEs, which were recently demonstrated to belong to a LINE family. Moreover, Bov-tA and Bov-B share the same 3'-end tail. We propose a possible scenario whereby the composite structure of the bovine Bov-tA family of SINEs might have been generated from the Bov-B family of LINEs during evolution.
我们的研究小组最近证明，几个tRNA衍生的短散在重复元件（SINEs）家族的3'末端起源于长散在重复元件（LINEs）的3'末端[大岛等人（1996年），《分子细胞生物学》16:3756 - 3764]。乌龟的Pol III/SINE和鲑科鱼类的HpaI SINE家族提供了两个这种结构的完整特征示例，烟草的TS SINE家族和鲑鱼的SmaI SINE家族提供了两个可能的示例。SINEs的这种结构可以解释它们在基因组中反转录转座的潜力，因为逆转录酶识别LINEs的位点位于LINEs的3'末端序列内似乎是合理的。我们现在为这类SINEs增加了另一个例子。在牛基因组中，有属于tRNA衍生SINEs超家族的Bov - tA SINEs，以及最近证明属于LINE家族的Bov - B LINEs。此外，Bov - tA和Bov - B共享相同的3'末端尾巴。我们提出了一种可能的情况：在进化过程中，牛的Bov - tA SINEs家族的复合结构可能是由Bov - B LINEs家族产生的。
