A PROPOSED SUPERFAMILY OF TRANSPOSASE GENES - TRANSPOSON-LIKE ELEMENTS IN CILIATED PROTOZOA AND A COMMON D35E MOTIF
A PROPOSED SUPERFAMILY OF TRANSPOSASE GENES - TRANSPOSON-LIKE ELEMENTS IN CILIATED PROTOZOA AND A COMMON D35E MOTIF
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DOI：
10.1073/pnas.91.3.942
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发表时间：
1994-02-01
影响因子：
11.1
通讯作者：
HERRICK, G
中科院分区：
文献类型：
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作者：
DOAK, TG;DOERDER, FP;HERRICK, G
腹毛类纤毛虫的类转座子元件TBE1、Tec1和Tec2似乎编码一种属于IS630 - Tc1转座酶家族的蛋白质。鱼腥藻IS895转座酶也被归入这一家族。我们注意到，大多数家族成员转座到二核苷酸靶位点TA，并且具有真核宿主的成员具有体细胞切除的倾向，纤毛虫元件将这种倾向发挥到了极致。包括新增成员以及水手元件的比对表明，该家族的转座酶在一个大的C末端部分具有高度保守的残基，包括一个完全保守的二肽天冬氨酸 - 谷氨酸（DE），以及一个由完全保守的天冬氨酸和高度保守的谷氨酸组成的模块，它们被34或35个残基隔开（D35E）。这个D35E基序可能与先前已鉴定的逆转录病毒 - 反转录转座子整合酶家族和IS3样转座酶的D35E基序同源。因为已知IS3 - 反转录转座子的D35E区域是一个能够进行各种体外转座相关反应的结构域的关键部分，所以这些结果表明这两个家族具有同源的催化转座酶结构域，并且两个家族的成员可能具有共同的转座机制。
The transposon-like elements TBE1, Tec1, and Tec2 of hypotrichous ciliated protozoa appear to encode a protein that belongs to the IS630-Tc1 family of transposases. The Anabaena IS895 transposase also is placed in this family. We note that most family members transpose into the dinucleotide target, TA, and that members with eukaryotic hosts have a tendency for somatic excision that is carried to an extreme by the ciliate elements. Alignments including the additional members, and also mariner elements, show that transposases of this family share strongly conserved residues in a large C-terminal portion, including a fully conserved dipeptide, Asp-Glu (DE), and a block consisting of a fully conserved Asp and highly conserved Glu, separated by 34 or 35 residues (D35E). This D35E motif likely is homologous to the previously characterized D35E motif of the family of retroviral-retrotransposon integrases and IS3-like transposases. Because it is known that the IS3-retroposon D35E region is a critical portion of a domain capable of various in vitro transposition-related reactions, the results suggest that the two families share homologous catalytic transposase domains and that members of both families may share a common transposition mechanism.