University of Szczecin, Faculty of Natural Sciences, Chair of Cell Biology, Waska 13, 71-415 Szczecin, Poland.
J Appl Genet. 2010;51(1):1-8. doi: 10.1007/BF03195704.
Employing FISH analysis as well as BLAST and CUSTAL W (1.82) programs, we investigated types of DNA nucleotide sequences building an additional heterochromatic band in 2R chromosomes of 3 lines of Secale vavilovii Grossh. The probes used in FISH analysis were designed based on the reverse transcriptase sequence of Ty1-copia and Ty3-gypsy retrotransposons and the 5S rRNA gene sequence. No hybridization signals from the reverse transcriptase probes were observed in the chromosome region where the additional band occurs. On the other hand, signals were observed after hybridization with the 5S rDNA probe, clearly suggesting the presence of that type of sequences in the analyzed heterochromatin band. Using BLAST and CUSTAL W programs, we revealed high similarity of the JNK1 sequence to the 5S rRNA gene from Hordeum chilense (HCH1016, HCH1018, 88%) and to a fragment of the 5S rRNA sequence of H. marinum (HMAR003, 97%). In addition, the same fragment of JNK1 was shown to be very similar to the part of the Angela retrotransposon (92%) as well as to the SNAC 426K20-1 transposon (89%) belonging to CACTA family, both from Triticum monococcum, and to Zingeria biebersteiniana pericentromeric sequences (78%). The similarity of JNK1 to those sequences may be accidental or the JNK1 may represent an ancient mobile genetic element that caught the 5S rRNA sequence. During the evolution those sequences might have been accumulated in the particular region on the 2R chromosome. Our results suggest that the additional heterochromatin band in chromosomes 2R of S. vavilovii is a collection of defective genes and/or mobile genetic elements.
运用 FISH 分析以及 BLAST 和 CUSTAL W（1.82）程序，我们研究了构建 3 条斯卑尔脱小麦（Secale vavilovii Grossh）2R 染色体额外异染色质带的 DNA 核苷酸序列类型。FISH 分析中使用的探针是基于 Ty1-copia 和 Ty3-gypsy 反转录转座子的反转录酶序列和 5S rRNA 基因序列设计的。在额外带发生的染色体区域没有观察到来自反转录酶探针的杂交信号。另一方面，在用 5S rDNA 探针杂交后观察到信号，这清楚地表明在分析的异染色质带中存在这种类型的序列。使用 BLAST 和 CUSTAL W 程序，我们揭示了 JNK1 序列与 Hordeum chilense（HCH1016、HCH1018，88%）和 H. marinum（HMAR003，97%）5S rRNA 序列片段的高度相似性。此外，JNK1 的相同片段与 Angela 反转座子（92%）以及 SNAC 426K20-1 转座子（89%）非常相似，这两个转座子都属于 CACTA 家族，来自 Triticum monococcum，以及 Zingeria biebersteiniana 着丝粒序列（78%）。JNK1 与这些序列的相似性可能是偶然的，或者 JNK1 可能代表捕获 5S rRNA 序列的古老移动遗传元件。在进化过程中，这些序列可能在 2R 染色体的特定区域积累。我们的结果表明，斯卑尔脱小麦 2R 染色体的额外异染色质带是缺陷基因和/或移动遗传元件的集合。
