Unstable transmission of rice chromosomes without functional centromeric repeats in asexual propagation
Unstable transmission of rice chromosomes without functional centromeric repeats in asexual propagation
复制标题
无性繁殖中没有功能性着丝粒重复的水稻染色体的不稳定传递
DOI：
10.1007/s10577-009-9073-7
复制
发表时间：
2009-10-01
影响因子：
2.6
通讯作者：
Gu, Minghong
中科院分区：
文献类型：
--
作者：
Gong, Zhiyun;Yu, Hengxiu;Gu, Minghong
在初级三体8的有性繁殖过程中，一些水稻植株的8号染色体断裂，导致端三体（2n+中心点8 S）系。在这项研究中，我们观察到8号染色体的额外短臂（center dot 8 S）在端三体中容易丢失，荧光原位杂交（FISH）分析表明，额外的中心点8 S的着丝粒区域不含水稻着丝粒卫星重复序列（CentO）和着丝粒特异反转录转座子（CRR）;然而，额外的中心点8 S含有最初保存的端三体系中的CentO和CRR序列的一部分。我们通过实时定量PCR（RQ-PCR）分析证实，额外中心点8 S的原始功能性着丝粒丢失。用FISH和RQ-PCR，额外的中心点8 S的断裂点被发现在BAC克隆a0070 J19序列内，该序列含有靠近8号染色体着丝粒区域的短臂的第一部分，但没有任何CentO或CRR序列。然而，a0070 J19 BAC克隆内的部分DNA序列在新的功能性着丝粒中发挥作用，导致水稻端三体无性繁殖植株在田间的形态变异。我们的结论是CENH 3，在真核动粒的关键元件，可能并不总是正确地结合新的功能性着丝粒，导致额外的中心点8 S在有丝分裂过程中的损失和染色体数目返回到二倍体水平在随后的几代。
During sexual propagation of primary trisomic 8, chromosome 8 breaks in some rice plants, resulting in a telotrisomic (2n+center dot 8S) line. In this study, we observed that the extra short arm of chromosome 8 (center dot 8S) can easily be lost in the telotrisomic, and we determined by fluorescence in-situ hybridization (FISH) analysis that the centromeric region of the extra center dot 8S did not contain the rice centromeric satellite repeat (CentO) and centromere-specific retrotransposon (CRR); however, the extra center dot 8S contained part of the CentO and CRR sequences in the initially preserved telotrisomic line. We confirmed by real-time quantitative PCR (RQ-PCR) analysis that the original functional centromere of the extra center dot 8S was lost. Using both FISH and RQ-PCR, the breakage point of the extra center dot 8S was found within the BAC clone a0070J19 sequence containing the first part of the short arm near the centromere region of chromosome 8 but without any CentO or CRR sequences. However, part of the DNA sequence within the a0070J19 BAC clone played a role in the new functional centromere, contributing to the morphological variations by asexually propagated plants of rice telotrisomics in the field. We conclude that CENH3, a key element in the eukaryotic kinetochore, may not always bind properly with the new functional centromere, resulting in loss of the extra center dot 8S during mitosis and the chromosome numbers returning to diploid levels in subsequent generations.