Wincker P, Jubier-Maurin V, Roizès G
CRBM-L.P 8402 CNRS, U.249 INSERM, Institut de Biologie, Montpellier, France.
Nucleic Acids Res. 1987 Nov 11;15(21):8593-606. doi: 10.1093/nar/15.21.8593.
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.
小鼠长散在重复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序列（A重复序列）相关联，这些A重复序列被认为是转录控制元件。我们报告称，在一些L1元件的5'端发现的另一种重复序列（称为F）也是全长L1拷贝的一个组成部分。测序表明，F重复序列富含GC，且呈串联排列。与A或F重复序列相关联的L1拷贝可以与L1序列的两个不同亚组相关，这两个亚组由各自特有的一系列变异核苷酸以及不相关但常见的限制性酶切位点区分。这些发现表明，L1Md的5'端至少发生过一次序列替换，并且与特定亚家族的产生有关。
