Unrelated sequences at the 5' end of mouse LINE-1 repeated elements define two distinct subfamilies.
Unrelated sequences at the 5' end of mouse LINE-1 repeated elements define two distinct subfamilies.
复制标题
小鼠 LINE-1 重复元件 5 端的不相关序列定义了两个不同的亚家族。
作者：
P. Wincker;V. Jubier;G. Roizes
小鼠长穿插重复DNA家族L1Md的一些全长成员已被证明在其5'端与可变数量的串联重复（a重复）相关，这已被认为是转录控制元件。我们报道了另一种类型的重复，称为F，在一些L1元素的5'端发现，也是全长L1拷贝的组成部分。测序结果表明，F重复序列富含GC，并且是串联的。与A或F重复序列相关的L1拷贝可以与两个不同的L1序列亚群相关，这些亚群由各自特有的一系列变异核苷酸和不相关但频繁的限制性位点区分。这些发现表明，L1Md的5'中至少发生了一次序列替换，并且与特定亚家族的产生有关。
Some full length members of the mouse long interspersed repeated DNA family L1Md have been shown to be associated at their 5' end with a variable number of tandem repetitions, the A repeats, that have been suggested to be transcription controlling elements. We report that the other type of repeat, named F, found at the 5' end of a few L1 elements is also an integral part of full length L1 copies. Sequencing shows that the F repeats are GC rich, and organized in tandem. The L1 copies associated with either A or F repeats can be correlated with two different subsets of L1 sequences distinguished by a series of variant nucleotides specific to each and by unassociated but frequent restriction sites. These findings suggest that sequence replacement has occurred at least once in 5' of L1Md, and is related to the generation of specific subfamilies.