PERSPECTIVES ON TUBULIN ISOTYPE FUNCTION AND EVOLUTION BASED ON THE OBSERVATION THAT TETRAHYMENA-THERMOPHILA MICROTUBULES CONTAIN A SINGLE ALPHA-TUBULIN AND BETA-TUBULIN
PERSPECTIVES ON TUBULIN ISOTYPE FUNCTION AND EVOLUTION BASED ON THE OBSERVATION THAT TETRAHYMENA-THERMOPHILA MICROTUBULES CONTAIN A SINGLE ALPHA-TUBULIN AND BETA-TUBULIN
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DOI：
10.1002/cm.970250305
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发表时间：
1993-01-01
影响因子：
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通讯作者：
GOROVSKY, MA
中科院分区：
文献类型：
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作者：
GAERTIG, J;THATCHER, TH;GOROVSKY, MA
我们克隆并测序了嗜热四膜虫纤毛原虫的两个β-微管蛋白基因。这两个基因编码相同的443个氨基酸多肽，与梨形毛虫β-微管蛋白的同源性为99.7%，与人β-微管蛋白的同源性为95%。嗜热葡萄球菌只含有一个α-微管蛋白基因(Callahan等人，1984：cell 36：441-445)。因此，这种单细胞生物体中所有极其多样化的微管结构都可以由单一的α-微管蛋白和单一的β-微管蛋白多肽形成。我们还对84个完整的β-微管蛋白多肽序列进行了系统发育分析。这一分析支持关于β-微管蛋白进化和功能的两个假说：1)多功能的β-微管蛋白比存在于特殊细胞或微管相关功能很少的细胞中的β-微管蛋白受到更大的进化限制，后者可以快速进化；2)形成轴丝的细胞维持着一个均一的微管蛋白群体。
We have cloned and sequenced the two beta-tubulin genes of the ciliated protozoan Tetrahymena thermophila. The two genes encode identical 443 amino acid peptides which are 99.7% identical to the beta-tubulin proteins of T. pyriformis and 95% identical to human beta1 tubulin. T. thermophila contains only one alpha-tubulin gene (Callahan et al., 1984: Cell 36:441-445). Thus, all of the extremely diverse microtubule structures in this unicellular organism can be formed from a single alpha- and a single beta-tubulin peptide. We have also carried out a phylogenetic analysis of 84 complete beta-tubulin peptide sequences. This analysis supports two hypotheses regarding beta-tubulin evolution and function: 1) Multifunctional beta-tubulins are under greater evolutionary constraint than beta-tubulins present in specialized cells or in cells with very few microtubule related functions, which can evolve rapidly; and 2) Cells which form axonemes maintain a homogeneous population of tubulins.