Aloe spp. – plants with vertebrate-like telomeric sequences
Aloe spp. – plants with vertebrate-like telomeric sequences
复制标题
芦荟属——具有类似脊椎动物端粒序列的植物
作者：
H. Weiss;H. Scherthan
大多数真核生物的染色体末端是短串联重复的富含GC的序列，其组成在不同的生物群体中有所不同。植物物种主要在其端粒处含有（TTTAGGG）n重复序列。然而，一些植物物种，包括葱科和芦荟属的成员。（Asphodelaceae）缺乏这样的端粒重复序列。最近，有人提出，T3 AG 3端粒重复序列的缺乏延伸到所有物种形成的芦笋分支。本文采用单引物PCR和荧光原位杂交技术，分别用直标芦荟型（TTTAGGG）28-43 DNA探针和脊椎动物型（TTAGGG）33-50 DNA探针及（C3 TA 2）3肽核酸（PNA）探针分析了芦荟端粒的组成。结果表明，烟草中含有拟南芥型端粒重复序列，而芦荟端粒缺乏相应的FISH信号。令人惊讶的是，用高度特异性脊椎动物型（C3 TA 2）3 PNA探针进行的FISH在芦荟和烟草的染色体末端都产生了强烈的T2 AG 3特异性FISH信号，表明这些物种中存在T2 AG 3端粒重复序列。长（TTAGGG）33-50 DNA探针的FISH也突出显示芦荟染色体末端，而该探针未能显示烟草染色体上的FISH信号。这些结果表明，在芦荟属物种的端粒脊椎动物样端粒序列的存在。染色体然而，使用（T2 AG 3）5引物的单引物PCR未能在芦荟中扩增出这样的序列，这可能表明在染色体末端的T2 AG 3重复和/或它们与其他重复类型的共取向和散布的拷贝数较低。我们的研究结果表明，植物物种的端粒，这被认为是缺乏GC丰富的重复序列，实际上可能包含变异的重复类型。
Chromosome termini of most eukaryotes end in tracks of short tandemly repeated GC-rich sequences, the composition of which varies among different groups of organisms. Plant species predominantly contain (TTTAGGG)n repeats at their telomeres. However, a few plant species, including members of Alliaceae and Aloe spp. (Asphodelaceae) were found to lack such Arabidopsis-type (T3AG3)n telomeric repeats. Recently, it has been proposed that the lack of T3AG3 telomeric repeat sequences extends to all species forming the Asparagales clade. Here, we analysed the composition of Aloe telomeres by single-primer PCR and fluorescence in-situ hybridization (FISH) with directly labelled Arabidopsis-type (TTTAGGG)28–43 DNA probe, and with vertebrate-type (TTAGGG)33–50 DNA and a (C3TA2)3 peptide nucleic acid (PNA) probe. It was found that Nicotiana tabacum contained Arabidopsis-type telomeric repeats, while Aloe telomeres lacked the corresponding FISH signals. Surprisingly, FISH with the highly specific vertebrate-type (C3TA2)3 PNA probe resulted in strong T2AG3-specific FISH signals at the ends of chromosomes of both Aloe and Nicotiana tabacum, suggesting the presence of T2AG3 telomeric repeats in these species. FISH with a long (TTAGGG)33–50 DNA probe also highlighted Aloe chromosome ends, while this probe failed to reveal FISH signals on tobacco chromosomes. These results indicate the presence of vertebrate-like telomeric sequences at the telomeres of Aloe spp. chromosomes. However, single-primer PCR with (T2AG3)5 primers failed to amplify such sequences in Aloe, which could indicate a low copy number of T2AG3 repeats at the chromosome ends and/or their co-orientation and interspersion with other repeat types. Our results suggest that telomeres of plant species, which were thought to lack GC-rich repeats, may in fact contain variant repeat types.
影响因子：
3.5
作者：
Lansdorp, PM;Verwoerd, NP;Tanke, HJ
通讯作者：
Tanke, HJ
DOI：
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发表时间：
1997
期刊：
Biochemistry. Biokhimiiyyyayyy.
影响因子：
--
作者：
McKnight,TD;Fitzgerald,MS;Shippen,DE
通讯作者：
Shippen,DE