Characterization of the centromere and peri-centromere retrotransposons in Brassica rapa and their distribution in related Brassica species
Characterization of the centromere and peri-centromere retrotransposons in Brassica rapa and their distribution in related Brassica species
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DOI：
10.1111/j.1365-313x.2006.02952.x
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发表时间：
2007-01-01
期刊：
影响因子：
7.2
通讯作者：
Park, Beom-Seok
中科院分区：
文献类型：
--
作者：
Lim, Ki-Byung;Yang, Tae-Jin;Park, Beom-Seok
我们报道了芜菁着丝粒和着丝粒周围异染色质中主要重复序列的鉴定和特征。该分析涉及88 629个细菌人工染色体（BAC）末端序列和两个BAC克隆的完整序列的表征。我们鉴定了芸苔属的着丝粒特异性反转录转座子（CRB）和各种着丝粒周围特异性反转录转座子（PCRBr）。在一个BAC克隆中鉴定了CRB的三个拷贝作为176 bp着丝粒重复序列CentBr的24个拷贝的串联阵列内的嵌套插入。在5S-25 SrDNA序列的衍生物中或附近发现了由9个PCRBr元件和238 bp的大片段简并串联重复序列（TR 238）组成的复杂嵌合结构。使用原位杂交确定所选重复序列的染色体位置。这些结果表明，CR 13是三种二倍体芸苔属植物及其异源四倍体近缘种所有着丝粒的主要组成部分。然而，CentBr在所分析的二倍体物种的最远亲缘关系中未检测到，B。黑鬼在B的4条染色体的着丝粒周围异染色质块中发现PCRBr和TR 238是主要成分。拉帕。在B中未识别出这些重复元件。oleracea或B.这表明它们是A基因组特异性的。
We report the identification and characterization of the major repeats in the centromeric and peri-centromeric heterochromatin of Brassica rapa. The analysis involved the characterization of 88 629 bacterial artificial chromosomes (BAC) end sequences and the complete sequences of two BAC clones. We identified centromere-specific retrotransposons of Brassica (CRB) and various peri-centromere-specific retrotransposons (PCRBr). Three copies of the CRB were identified in one BAC clone as nested insertions within a tandem array of 24 copies of a 176 bp centromeric repeat, CentBr. A complex mosaic structure consisting of nine PCRBr elements and large blocks of 238 bp degenerate tandem repeats (TR238) were found in or near a derivative of 5S-25S rDNA sequences. The chromosomal positions of selected repeats were determined using in situ hybridization. These revealed that CR13 is a major component of all centromeres in three diploid Brassica species and their allotetraploid relatives. However, CentBr was not detected in the most distantly related of the diploid species analyzed, B. nigra. PCRBr and TR238 were found to be major components in the pericentromeric heterochromatin blocks of four chromosomes of B. rapa. These repetitive elements were not identified in B. oleracea or B. nigra, indicating that they are A-genome-specific.