Distribution of retroelements in centromeres and neocentromeres of maize.
Distribution of retroelements in centromeres and neocentromeres of maize.
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发表时间：
2003-10
期刊：
影响因子：
3.3
通讯作者：
Rebecca J Mroczek;R. Dawe
中科院分区：
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作者：
Rebecca J Mroczek;R. Dawe
采用荧光原位杂交技术检测了6个丰富的长末端重复（LTR）逆转录因子Opie、Huck、cinful1、Prem-2/Ji、Grande和Tekay/Prem-1在玉米粗线染色体上的分布。逆转录因子在常染色质上的染色是非常均匀的，即使我们在我们的分析中包括了结构多态性异常的10号染色体（Ab10）。这种均匀性使得在基因组的其他区域使用常染色质作为定量染色强度测量的控制成为可能。数据显示，当Ab10存在时，旋钮被认为具有兼性新中心粒的功能，它倾向于排除逆转录因子。一个值得注意的例外是cinful1，它在TR-1旋钮数组中积累。在着丝体卫星阵列中，这六种逆转录因子的染色也大大减少，平均为常染色质染色的30%。这与先前描述的两种在着丝粒中容易检测到的着丝粒特异性反转录转座（CR）元素形成对比。我们认为逆转录因子在着丝粒中相对罕见，因为它们中断了被认为是有效的着丝粒功能所必需的长卫星阵列。CR元件可能与它们的植物寄主进化出了互惠关系：已知它们与着丝点蛋白CENH3相互作用，并且似乎聚集在一起，留下完整的长卫星阵列。
Fluorescent in situ hybridization was used to examine the distribution of six abundant long terminal repeat (LTR) retroelements, Opie, Huck, Cinful-1, Prem-2/Ji, Grande, and Tekay/Prem-1 on maize pachytene chromosomes. Retroelement staining in euchromatin was remarkably uniform, even when we included the structurally polymorphic abnormal chromosome 10 (Ab10) in our analysis. This uniformity made it possible to use euchromatin as a control for quantitative staining intensity measurements in other regions of the genome. The data show that knobs, known to function as facultative neocentromeres when Ab10 is present, tend to exclude retroelements. A notable exception is Cinful-1, which accumulates in TR-1 knob arrays. Staining for each of the six retroelements was also substantially reduced in centromeric satellite arrays to an average of 30% of the staining in euchromatin. This contrasted with two previously described centromere-specific retrotransposable (CR) elements that were readily detected in centromeres. We suggest that retroelements are relatively rare in centromeres because they interrupt the long satellite arrays thought to be required for efficient centromere function. CR elements may have evolved mutualistic relationships with their plant hosts: they are known to interact with the kinetochore protein CENH3 and appear to accumulate in clusters, leaving long satellite arrays intact.