Structural heterogeneity in the R173 family of rye-specific repetitive DNA sequences
Structural heterogeneity in the R173 family of rye-specific repetitive DNA sequences
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DOI：
10.1007/bf00029152
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发表时间：
1992-10
影响因子：
5.1
通讯作者：
P. Rogowsky;Jin-yuan Liu;S. Manning;Christopher Taylor;P. Langridge
中科院分区：
文献类型：
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作者：
P. Rogowsky;Jin-yuan Liu;S. Manning;Christopher Taylor;P. Langridge
黑麦特异性R173家族的重复DNA序列由约100个核苷酸组成。黑麦（Secale cereale）基因组中含有15000个拷贝，并以分散的方式分布在所有7条染色体上。单个R173元件的大小在3和6 kb之间变化，通常不排列为串联重复序列，并且侧接多拷贝和单拷贝序列。3个R173元件（R173-1、R173-2和R173-3）的DNA序列分析表明，在保守结构域中具有高度的同源性。R173-1的结构与其他两个元件有很大不同：在末端发现了代表黑麦特异性重复序列的长直接重复序列，并且一个600 bp长的结构域被一个大小大致相等的不相关序列取代。R173-2和R173-3彼此极其相似，除了R173-2的末端截短。不存在>20 kDa蛋白质的开放阅读框，并且数据库搜索未能检测到与公开的蛋白质序列的显著同源性。尽管R173家族的基因组组织类似于转座子，但个别元件缺乏通常与转座子和反转录转座子相关的序列特征。与此相反，R173元件两侧的两个区域显示出强烈的DNA同源性，一个850 bp长的区域的建议小麦反转录转座子和一个300 bp长的区域的wheatGlu-D1基因下游。
The rye-specific R173 family of repeated DNA sequences consists of ca. 15 000 individual copies per diploid rye (Secale cereale) genome and is distributed over all 7 rye chromosomes in a dispersed manner. Individual R173 elements vary in size between 3 and 6 kb, are generally not arranged as tandem repeats and are flanked by both multi-copy and single-copy sequences. DNA sequence analysis of three R173 elements (R173-1, R173-2 and R173-3) demonstrated a high degree of homology in conserved domains. The structure of R173-1 was quite different from the other two elements: long direct repeats, which represent a rye-specific repetitive sequence, were found at the ends and a 600 bp long domain was replaced by an unrelated sequence of approximately equal size. R173-2 and R173-3 were extremely similar to each other with the exception of a terminal truncation of R173-2. No open reading frames for proteins >20 kDa were present and a database search failed to detect significant homologies to published protein sequences. Despite the transposon like genomic organisation of the R173 family, individual elements lacked sequence features frequently associated with transposons and retrotransposons. In contrast, two of the regions flanking R173 elements showed strong DNA homologies to a 850 bp long region of a proposed wheat retrotransposon and to a 300 bp long region downstream of the wheatGlu-D1gene.