Structure, chromosome location, and expression of the human smooth muscle (enteric type) gamma-actin gene: evolution of six human actin genes
Structure, chromosome location, and expression of the human smooth muscle (enteric type) gamma-actin gene: evolution of six human actin genes
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人类平滑肌（肠型）γ-肌动蛋白基因的结构、染色体位置和表达：六个人类肌动蛋白基因的进化
DOI：
10.1128/mcb.11.6.3296-3306.1991
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发表时间：
1991
影响因子：
5.3
通讯作者：
Takeo Kakunaga
中科院分区：
文献类型：
--
作者：
Takeshi Miwa;Y. Manabe;Kazuo Kurokawa;Shinji Kamada;N. Kanda;G. Bruns;H. Ueyama;Takeo Kakunaga
从人基因组DNA文库中分离到携带人平滑肌(肠型)γ-肌动蛋白基因的重组噬菌体。从核苷酸序列推导出的氨基酸序列与cDNA的氨基酸序列匹配，但与先前报道的一个氨基酸位置的蛋白质序列不同，密码子359。该基因包含1个5‘未翻译外显子和8个编码外显子，在人类2号染色体上长27kb。位于密码子84和85(第3位)之间的内含子是这两个平滑肌肌动蛋白基因所特有的。在5‘侧翼区域，有几个Carg盒和E盒，它们是一些肌肉特异基因的调控元件。与3‘端非翻译区的杂交表明，该基因存在于人类基因组中，并在肠道和主动脉组织中特异表达。根据六个人肌动蛋白亚型基因的分子结构特征，我们提出了肌动蛋白基因家族进化途径的假说。一个推测的祖先肌动蛋白基因至少有1、2和4到8个内含子。细胞质肌动蛋白基因可能是通过丢失5和6个内含子直接进化而来的。然而，通过复制祖先肌动蛋白基因并替换许多氨基酸，已经创建了肌肉肌动蛋白基因的原型。随后，横纹肌肌动蛋白和平滑肌肌动蛋白基因可能分别通过丢失第4位内含子和获得第3位新内含子而从该原型进化而来。
Recombinant phages that carry the human smooth muscle (enteric type) gamma-actin gene were isolated from human genomic DNA libraries. The amino acid sequence deduced from the nucleotide sequence matches those of cDNAs but differs from the protein sequence previously reported at one amino acid position, codon 359. The gene containing one 5' untranslated exon and eight coding exons extends for 27 kb on human chromosome 2. The intron between codons 84 and 85 (site 3) is unique to the two smooth muscle actin genes. In the 5' flanking region, there are several CArG boxes and E boxes, which are regulatory elements in some muscle-specific genes. Hybridization with the 3' untranslated region, which is specific for the human smooth muscle gamma-actin gene, suggests the single gene in the human genome and specific expressions in enteric and aortic tissues. From characterized molecular structures of the six human actin isoform genes, we propose a hypothesis of evolutionary pathway of the actin gene family. A presumed ancestral actin gene had introns at least sites 1, 2, and 4 through 8. Cytoplasmic actin genes may have directly evolved from it through loss of introns at sites 5 and 6. However, through duplication of the ancestral actin gene with substitutions of many amino acids, a prototype of muscle actin genes had been created. Subsequently, striated muscle actin and smooth muscle actin genes may have evolved from this prototype by loss of an intron at site 4 and acquisition of a new intron at site 3, respectively.