Lipikhina Yu A, Evtushenko E V, Gatskaya S S, Stepochkin P I, Lyusikov O M, Gordey I A, Vershinin A V
Tsitologiia. 2016;58(4):324-9.
Chromosome elimination of one parental species in hybrid cell observed even after successful fertilization is one of a common phenomenon and the main problems of remote hybridization. Centromeres regulate the process of faithful segregation of chromosomes during cell division. Constant component of the centromeric chromatin is a specialized histone H3 modification (CENH3). CENH3 consists of a conserved C-terminal domain (HFD) and a more variable N-terminal tail (NTT), which plays an important role for CENH3 loading in centromeric chromatin during cell division. In the present study, we performed comparative analysis of CENH3 variants expression in allopolyploids, as well as in different parental varieties of rye (Secale cereale L.) and wheat (Triticum aestivum L.). The varieties of both genera were used as maternal plants. In the coding sequences of the NTT CENH3 we identified the full-length copies of 216 bp with characteristic single nucleotide polymorphisms (SNPs), and copies with 21 bp or 66 bp deletions. The wheat and rye NTT CENH3 copies with 21 bp deletion have not differences in the nucleotide sequences, the rye copies with 66 bp deletion reveal two specific SNPs, which were also found in plant of wheat-rye allopolyploids having 57 chromosomes. The full-length sequences of rye NTT CENH3 show specific SNPs, which were also detected in the full-length sequences of all analyzed plants of wheat-rye allopolyploids. These results indicate that expression of CENH3 copies belonging to each parent was observed in hybrid genomes of aneuploids which arose from octoploid triticale. The NTT CENH3 copies with deletions were not found in secalotriticum (Secalotriticum). The full-length sequences show two rye specific SNPs. Their frequency in secalotriticum significantly exceeds that in hexaploid triticale Mikhas. This fact points to the preferential synthesis of the full NTT CENH3 copies of the rye parental variety in the secalotriticum genome.
即使在成功受精后,杂种细胞中一个亲本物种的染色体消除也是常见现象之一,也是远缘杂交的主要问题。着丝粒在细胞分裂过程中调节染色体的忠实分离过程。着丝粒染色质的恒定成分是一种特殊的组蛋白H3修饰(CENH3)。CENH3由一个保守的C端结构域(HFD)和一个变化较大的N端尾巴(NTT)组成,NTT在细胞分裂过程中CENH3加载到着丝粒染色质中起重要作用。在本研究中,我们对异源多倍体以及黑麦(Secale cereale L.)和小麦(Triticum aestivum L.)不同亲本品种中CENH3变体的表达进行了比较分析。两个属的品种都用作母本植物。在NTT CENH3的编码序列中,我们鉴定出了具有特征性单核苷酸多态性(SNP)的216 bp全长拷贝,以及具有21 bp或66 bp缺失的拷贝。小麦和黑麦具有21 bp缺失的NTT CENH3拷贝在核苷酸序列上没有差异,具有66 bp缺失的黑麦拷贝显示出两个特定的SNP,在具有57条染色体的小麦-黑麦异源多倍体植物中也发现了这些SNP。黑麦NTT CENH3的全长序列显示出特定的SNP,在所有分析的小麦-黑麦异源多倍体植物的全长序列中也检测到了这些SNP。这些结果表明,在源自八倍体小黑麦的非整倍体杂种基因组中观察到了属于每个亲本的CENH3拷贝的表达。在节节麦(Secalotriticum)中未发现具有缺失的NTT CENH3拷贝。全长序列显示出两个黑麦特异性SNP。它们在节节麦中的频率显著超过六倍体小黑麦米哈斯(Mikhas)中的频率。这一事实表明,在节节麦基因组中优先合成了黑麦亲本品种的完整NTT CENH3拷贝。