Isolation and sequence analysis of the wheat B genome subtelomeric DNA
Isolation and sequence analysis of the wheat B genome subtelomeric DNA
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DOI：
10.1186/1471-2164-10-414
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发表时间：
2009-09-05
期刊：
影响因子：
4.4
通讯作者：
Chalhoub, Boulos
中科院分区：
文献类型：
--
作者：
Salina, Elena A.;Sergeeva, Ekaterina M.;Chalhoub, Boulos
背景：端粒和亚端粒区对基因组的稳定性和正常的染色体复制至关重要。本研究对小麦BAC（bacterial artificial chromosome）克隆进行了特征分析，克隆中含有Spelt 1和Spelt 52序列，它们属于Sitopsis组小麦和山羊草属植物基因组的B/G亚端粒重复序列。以Spelt 1和Spelt 52为探针筛选Renan。共分离到9个阳性克隆，其中克隆2050 O 8主要定位于小麦染色体的远端部分。其他克隆的分布表明BAC中存在不同类型的重复序列。使用不同的方法使我们能够证明，七个分离的克隆属于亚端粒染色体区域。对克隆2050 O 8进行测序，并对119737 bp的序列进行了注释。它由33%的转座因子（TE）、8.2%的Spelt 52（即Spelt52.2亚家族）和5个非TE相关基因组成。DNA转座子占优势，占整个BAC克隆的24.6%，而逆转录元件占克隆长度的8.4%。CACTA转座子Caspar全长11 666 bp，编码转座酶和CTG-2蛋白，占转座子总数的40%。2050 O 8衍生的亚克隆的原位杂交数据结合对小麦定位的EST（表达序列标签）的BLAST搜索表明，克隆2050 O 8位于末端bin 4 BL-10（0.95-1.0）。此外，预测的2050 O 8基因中有4个与水稻3S染色体远端的4个可能的水稻直体基因具有显著的同源性，并与小麦4 BL基因具有同线性。结论：小麦二倍体祖先染色体亚端粒区的卫星DNA序列可用于从六倍体小麦染色体相应区域中筛选BAC克隆。首次证明Spelt 52序列参与了普通小麦染色体末端区域的进化。我们的研究为小麦4 BL和水稻3S染色体末端区域的微共线性提供了新的认识。
Background: Telomeric and subtelomeric regions are essential for genome stability and regular chromosome replication. In this work, we have characterized the wheat BAC (bacterial artificial chromosome) clones containing Spelt1 and Spelt52 sequences, which belong to the subtelomeric repeats of the B/G genomes of wheats and Aegilops species from the section Sitopsis.Results: The BAC library from Triticum aestivum cv. Renan was screened using Spelt1 and Spelt52 as probes. Nine positive clones were isolated; of them, clone 2050O8 was localized mainly to the distal parts of wheat chromosomes by in situ hybridization. The distribution of the other clones indicated the presence of different types of repetitive sequences in BACs. Use of different approaches allowed us to prove that seven of the nine isolated clones belonged to the subtelomeric chromosomal regions. Clone 2050O8 was sequenced and its sequence of 119 737 bp was annotated. It is composed of 33% transposable elements (TEs), 8.2% Spelt52 (namely, the subfamily Spelt52.2) and five non-TE-related genes. DNA transposons are predominant, making up 24.6% of the entire BAC clone, whereas retroelements account for 8.4% of the clone length. The full-length CACTA transposon Caspar covers 11 666 bp, encoding a transposase and CTG-2 proteins, and this transposon accounts for 40% of the DNA transposons. The in situ hybridization data for 2050O8 derived subclones in combination with the BLAST search against wheat mapped ESTs (expressed sequence tags) suggest that clone 2050O8 is located in the terminal bin 4BL-10 (0.95-1.0). Additionally, four of the predicted 2050O8 genes showed significant homology to four putative orthologous rice genes in the distal part of rice chromosome 3S and confirm the synteny to wheat 4BL.Conclusion: Satellite DNA sequences from the subtelomeric regions of diploid wheat progenitor can be used for selecting the BAC clones from the corresponding regions of hexaploid wheat chromosomes. It has been demonstrated for the first time that Spelt52 sequences were involved in the evolution of terminal regions of common wheat chromosomes. Our research provides new insights into the microcollinearity in the terminal regions of wheat chromosomes 4BL and rice chromosome 3S.