Phillips S J, Hardies S C, Jahn C L, Edgell M H, Hutchison C A
J Biol Chem. 1984 Jun 25;259(12):7947-54.
We have determined the complete nucleotide sequence of beta h2, a pseudogene in the mouse beta-globin gene complex. The structure of beta h2 is analogous to that of a normal beta-globin gene, and its nucleotide sequence shares 72% homology with the coding regions of a reference mouse adult beta-globin gene. A frame shift occurs in the first coding region for which a compensatory splicing scheme can be devised. The reading frame is not otherwise disrupted. All of the recognized transcription, translation, and splicing signals in beta h2 are intact, with the exception of the " CCAAT box," which has been altered to GTAAC . We compared the predicted amino acid sequence of beta h2 with other beta-globin sequences. Evidence for a period of divergence without selection in the history of beta h2 was found in a set of codons that are usually highly conserved in productive beta-globin genes. An evolutionary tree constructed from nucleotide sequence suggests that beta h2 originated from the adult genes at least 60 million years ago. After some period as a productive gene, beta h2 was inactivated and has subsequently diverged without selection. Hybridization experiments demonstrated that beta h2 and the surrounding region occur without major alteration in other rodent species. The sequence ( AGCCA - 4n - GTGT ) occurs 5' of the CCAAT box in beta h2 and in many productive globin genes.
我们已经确定了小鼠β-珠蛋白基因复合体中的假基因βh2的完整核苷酸序列。βh2的结构类似于正常β-珠蛋白基因的结构，其核苷酸序列与参考小鼠成年β-珠蛋白基因的编码区有72%的同源性。在第一个编码区发生了移码，对此可以设计一种补偿性剪接方案。阅读框在其他方面未被破坏。βh2中所有公认的转录、翻译和剪接信号都是完整的，除了“CCAAT盒”已被改变为GTAAC。我们将βh2的预测氨基酸序列与其他β-珠蛋白序列进行了比较。在一组通常在有功能的β-珠蛋白基因中高度保守的密码子中，发现了βh2历史上存在一段无选择分化期的证据。根据核苷酸序列构建的进化树表明，βh2至少在6000万年前起源于成年基因。在作为一个有功能的基因存在一段时间后，βh2失活，随后在无选择的情况下发生了分化。杂交实验表明，βh2及其周围区域在其他啮齿动物物种中没有重大改变。序列（AGCCA - 4n - GTGT）出现在βh2和许多有功能的珠蛋白基因的CCAAT盒的5'端。
