Differential replication and DNA elimination in the polytene chromosomes of Euplotes crassus
Differential replication and DNA elimination in the polytene chromosomes of Euplotes crassus
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DOI：
10.1091/mbc.7.5.755
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发表时间：
1996-05-01
影响因子：
3.3
通讯作者：
Jahn, CL
中科院分区：
文献类型：
--
作者：
Frels, JS;Tebeau, CM;Jahn, CL
在发育中的大核中，粗游仆虫的转座子样Tec元件在多线染色体形成过程中被精确切除。为了确定是否所有的Tec元件表现出相同的发育时间切除，我们使用聚合酶链反应，可视化扩增和减少在许多随机选择的Tec插入位点。两类网站是显而易见的。早期复制位点显示一轮或多轮扩增和减少（对应于切除），并且经常发生在大核序列中。晚期复制位点不经历减少，直到染色体片段化，并主要与消除的序列，我们得出结论，前面描述的集群的大核注定的序列在微核基因组中允许他们的差异复制在多线期，并在靶向这些序列的转录激活和高度特异性的删除和染色体片段化过程。
The transposon-like Tec elements of Euplotes crassus are precisely excised during formation of polytene chromosomes in the developing macronucleus. To determine whether all Tec elements exhibit identical developmental timing of excision, we used polymerase chain reaction to visualize amplification and diminution at numerous randomly selected Tec insertion sites. Two classes of sites are evident. Early replicating sites show one or more rounds of amplification and diminution (corresponding to excision) and frequently occur within macronuclear-destined sequences. Late replicating sites do not undergo diminution until chromosome fragmentation and are predominantly associated with eliminated sequences, We conclude that the previously described clustering of macronuclear-destined sequences in the micronuclear genome allows for their differential replication at the polytene stage and results in targeting of these sequences for transcriptional activation and highly specific deletion and chromosome fragmentation processes.