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Rapid Birth or Death of Centromeres on Fragmented Chromosomes in Maize
Yalin Liu, Handong Su, Jing Zhang, Lindan Shi, Yang Liu, Bing Zhang, Han Bai, Shuang Liang, Zhi Gao, James A. Birchler, Fangpu Han
The Plant Cell
Abstract
Comparative genomics has revealed common occurrences in karyotype evolution such as chromosomal end-to-end fusions and insertions of one chromosome into another near the centromere as well as many cases of de novo centromeres that generate position polymorphism. These findings raise the conundrum of how such rearrangements as dicentrics and acentrics can persist without the initial chromosome being destroyed or lost. Here we sought experimental evidence for the frequency and timeframe for centromere inactivation and de novo formation. The pollen from plants with supernumerary B chromosomes was gamma irradiated and then applied to normal maize silks of a line without B chromosomes. Among ~8000 first generation seedlings, many B-A translocations as well as centromere expansions and ring chromosomes were recognized. Many dicentric chromosomes were also found but a fraction of these show only a single primary constriction suggesting inactivation of one centromere. Also, chromosomal fragments were found without canonical centromere sequences, which revealed the presence of de novo centromere formation over unique sequences. Examples were validated by immunolocalization studies with H2ApThr133, a marker of active centromeres, and ChIPseq with CENH3 antibody to reveal the sites of de novo centromeres. These results illustrate the regular occurrence of both centromere birth and death following chromosomal rearrangement and that these events occur during a narrow developmental window spanning one to potentially only a few cell cycles in order for the rearranged chromosomes to be recognized in this experimental regime.
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论文编号: |
DOI:10.1105/tpc.20.00389 |
论文题目: |
Rapid Birth or Death of Centromeres on Fragmented Chromosomes in Maize |
英文论文题目: |
Rapid Birth or Death of Centromeres on Fragmented Chromosomes in Maize |
第一作者: |
Yalin Liu, Handong Su, Jing Zhang, Lindan Shi, Yang Liu, Bing Zhang, Han Bai, Shuang Liang, Zhi Gao, James A. Birchler, Fangpu Han |
英文第一作者: |
Yalin Liu, Handong Su, Jing Zhang, Lindan Shi, Yang Liu, Bing Zhang, Han Bai, Shuang Liang, Zhi Gao, James A. Birchler, Fangpu Han |
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2020-08-19 |
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摘要: |
Comparative genomics has revealed common occurrences in karyotype evolution such as chromosomal end-to-end fusions and insertions of one chromosome into another near the centromere as well as many cases of de novo centromeres that generate position polymorphism. These findings raise the conundrum of how such rearrangements as dicentrics and acentrics can persist without the initial chromosome being destroyed or lost. Here we sought experimental evidence for the frequency and timeframe for centromere inactivation and de novo formation. The pollen from plants with supernumerary B chromosomes was gamma irradiated and then applied to normal maize silks of a line without B chromosomes. Among ~8000 first generation seedlings, many B-A translocations as well as centromere expansions and ring chromosomes were recognized. Many dicentric chromosomes were also found but a fraction of these show only a single primary constriction suggesting inactivation of one centromere. Also, chromosomal fragments were found without canonical centromere sequences, which revealed the presence of de novo centromere formation over unique sequences. Examples were validated by immunolocalization studies with H2ApThr133, a marker of active centromeres, and ChIPseq with CENH3 antibody to reveal the sites of de novo centromeres. These results illustrate the regular occurrence of both centromere birth and death following chromosomal rearrangement and that these events occur during a narrow developmental window spanning one to potentially only a few cell cycles in order for the rearranged chromosomes to be recognized in this experimental regime. |
英文摘要: |
Comparative genomics has revealed common occurrences in karyotype evolution such as chromosomal end-to-end fusions and insertions of one chromosome into another near the centromere as well as many cases of de novo centromeres that generate position polymorphism. These findings raise the conundrum of how such rearrangements as dicentrics and acentrics can persist without the initial chromosome being destroyed or lost. Here we sought experimental evidence for the frequency and timeframe for centromere inactivation and de novo formation. The pollen from plants with supernumerary B chromosomes was gamma irradiated and then applied to normal maize silks of a line without B chromosomes. Among ~8000 first generation seedlings, many B-A translocations as well as centromere expansions and ring chromosomes were recognized. Many dicentric chromosomes were also found but a fraction of these show only a single primary constriction suggesting inactivation of one centromere. Also, chromosomal fragments were found without canonical centromere sequences, which revealed the presence of de novo centromere formation over unique sequences. Examples were validated by immunolocalization studies with H2ApThr133, a marker of active centromeres, and ChIPseq with CENH3 antibody to reveal the sites of de novo centromeres. These results illustrate the regular occurrence of both centromere birth and death following chromosomal rearrangement and that these events occur during a narrow developmental window spanning one to potentially only a few cell cycles in order for the rearranged chromosomes to be recognized in this experimental regime. |
刊物名称: |
The Plant Cell |
英文刊物名称: |
The Plant Cell |
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其它备注: |
Yalin Liu, Handong Su, Jing Zhang, Lindan Shi, Yang Liu, Bing Zhang, Han Bai, Shuang Liang, Zhi Gao, James A. Birchler, Fangpu Han. Rapid Birth or Death of Centromeres on Fragmented Chromosomes in Maize. The Plant Cell. DOI:10.1105/tpc.20.00389 |
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