ACTIVE MAIZE GENES ARE UNMODIFIED AND FLANKED BY DIVERSE CLASSES OF MODIFIED, HIGHLY REPETITIVE DNA
ACTIVE MAIZE GENES ARE UNMODIFIED AND FLANKED BY DIVERSE CLASSES OF MODIFIED, HIGHLY REPETITIVE DNA
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DOI：
10.1139/g94-081
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发表时间：
1994-08-01
期刊：
影响因子：
3.1
通讯作者：
SANMIGUEL, P
中科院分区：
文献类型：
--
作者：
BENNETZEN, JL;SCHRICK, K;SANMIGUEL, P
我们的特点是拷贝数，组织和基因组修饰的DNA序列内和侧翼几个玉米基因。我们发现，高度重复的DNA序列与这些基因中的大多数紧密相连。在编码区内没有发现高度重复的序列，但在结构基因的3'或5'端的6 kb内可以发现。这些高度重复区域均由不同短重复序列的独特组合组成。高度重复的DNA块没有被任何检测到的单拷贝DNA中断。13类高度重复的DNA鉴定发现不同的玉米分离株之间变化不大。通过用限制酶对63个识别/切割位点的消化率进行评分来确定这些基因中和附近的DNA甲基化水平，所述限制酶对序列5 '-CG-3'和5 '-CNG-3'中胞嘧啶的5-甲基化敏感。除了四个位点外，所有这些位点在染色体DNA中都是可消化的。4个未消化位点位于基因外DNA中或附近的高重复DNA中，而其他59个位点位于低拷贝数DNA中。脉冲场凝胶分析表明，大多数胞嘧啶修饰的道的大小范围从20至200 kb。单拷贝序列与未修饰的结构域杂交，而高度重复的序列与修饰的区域杂交。在两个结构域中都发现了中等重复序列。
We have characterized the copy number, organization, and genomic modification of DNA sequences within and flanking several maize genes. We found that highly repetitive DNA sequences were tightly linked to most of these genes. The highly repetitive sequences were not found within the coding regions but could be found within 6 kb either 3' or 5' to the structural genes. These highly repetitive regions were each composed of unique combinations of different short repetitive sequences. Highly repetitive DNA blocks were not interrupted by any detected single copy DNA. The 13 classes of highly repetitive DNA identified were found to vary little between diverse Zea isolates. The level of DNA methylation in and near these genes was determined by scoring the digestibility of 63 recognition/cleavage sites with restriction enzymes that were sensitive to 5-methylation of cytosines in the sequences 5'-CG-3' and 5'-CNG-3'. All but four of these sites were digestible in chromosomal DNA. The four undigested sites were localized to extragenic DNA within or near highly repetitive DNA, while the other 59 sites were in low copy number DNAs. Pulsed field gel analysis indicated that the majority of cytosine modified tracts range from 20 to 200 kb in size. Single copy sequences hybridized to the unmodified domains, while highly repetitive sequences hybridized to the modified regions. Middle repetitive sequences were found in both domains.