Hassouna N, Michot B, Bachellerie J P
Nucleic Acids Res. 1984 Apr 25;12(8):3563-83. doi: 10.1093/nar/12.8.3563.
We have determined the complete nucleotide sequence (4712 nucleotides) of the mouse 28S rRNA gene. Comparison with all other homologs indicates that the potential for major variations in size during the evolution has been restricted to a unique set of a few sites within a largely conserved secondary structure core. The D (divergent) domains, responsible for the large increase in size of the molecule from procaryotes to higher eukaryotes, represent half the mouse 28S rRNA length. They show a clear potential to form self-contained secondary structures. Their high GC content in vertebrates is correlated with the folding of very long stable stems. Their comparison with the two other vertebrates, xenopus and rat, reveals an history of repeated insertions and deletions. During the evolution of vertebrates, insertion or deletion of new sequence tracts preferentially takes place in the subareas of D domains where the more recently fixed insertions/deletions were located in the ancestor sequence. These D domains appear closely related to the transcribed spacers of rRNA precursor but a sizable fraction displays a much slower rate of sequence variation.
我们已经确定了小鼠28S rRNA基因的完整核苷酸序列（4712个核苷酸）。与所有其他同源序列的比较表明，在进化过程中大小发生重大变化的可能性已被限制在一个高度保守的二级结构核心内的一组独特的少数位点上。D（发散）结构域导致了从原核生物到高等真核生物分子大小的大幅增加，占小鼠28S rRNA长度的一半。它们显示出形成独立二级结构的明显潜力。它们在脊椎动物中的高GC含量与非常长的稳定茎的折叠有关。将它们与另外两种脊椎动物非洲爪蟾和大鼠进行比较，揭示了重复插入和缺失的历史。在脊椎动物的进化过程中，新序列片段的插入或缺失优先发生在D结构域的子区域，这些子区域是最近在祖先序列中固定插入/缺失的位置。这些D结构域似乎与rRNA前体的转录间隔区密切相关，但相当一部分显示出慢得多的序列变异速率。
