Vivas M V, García-Planells J, Ruiz C, Marfany G, Paricio N, Gonzàlez-Duarte R, de Frutos R
Departamento de Genética, Facultad de Ciencias Biológicas, Dr. Moliner 50, Burjassot 46100, Valencia, Spain.
Gene. 1999 Mar 18;229(1-2):47-57. doi: 10.1016/s0378-1119(99)00031-1.
GEM is a new family of repetitive sequences detected in the D. subobscura genome. Two of the four described GEM elements encompass a heterogeneous central module, with no detectable ORF, flanked by two long inverted repeats. These elements are composed of a set of repetitive modules, which are inverted repeat (IR), direct repeat (DR), palindromic sequence (PS), long sequence (LS) and short sequence (SS). These five modules can be found either clustered or dispersed as single modules in the D. subobscura genome, in euchromatic and heterochromatic regions. In addition to the 3' region of Adh retrosequences, single IR and LS blocks were found associated with the promoter region of different genes, in particular, LS-like blocks have also been found associated with functional genes in D. melanogaster and D. virilis. Conversely, the DR block is highly similar to satellite DNAs from some other species of the obscura group. In addition, GEM elements share some structural features with IS elements described in different Drosophila species. It is likely that both GEM and IS sequences would be vestiges of an ancestral transposable element.
GEM是在暗果蝇基因组中检测到的一个新的重复序列家族。所描述的四个GEM元件中的两个包含一个异质中央模块，没有可检测到的开放阅读框，两侧是两个长反向重复序列。这些元件由一组重复模块组成，即反向重复序列（IR）、正向重复序列（DR）、回文序列（PS）、长序列（LS）和短序列（SS）。在暗果蝇基因组的常染色质和异染色质区域，这五个模块既可以成簇存在，也可以作为单个模块分散存在。除了Adh逆转录序列的3'区域外，还发现单个IR和LS块与不同基因的启动子区域相关，特别是，在黑腹果蝇和拟果蝇中也发现了类似LS的块与功能基因相关。相反，DR块与暗果蝇组其他一些物种的卫星DNA高度相似。此外，GEM元件与在不同果蝇物种中描述的IS元件具有一些结构特征。GEM和IS序列很可能都是祖先转座元件的遗迹。
