Noël C, Gerbod D, Fast N M, Wintjens R, Delgado-Viscogliosi P, Doolittle W F, Viscogliosi E
Institut Pasteur, INSERM U547, Lille, France.
J Eukaryot Microbiol. 2001 Nov-Dec;48(6):647-54. doi: 10.1111/j.1550-7408.2001.tb00204.x.
We have isolated and analysed an alpha-tubulin-encoding gene (atub1) in an early-diverging eukaryote, Trichomonas vaginalis. The complete atub1 open reading frame included 1.356 bp encoding a polypeptide of 452 amino-acyl residues. A second alpha-tubulin gene (atub2) was amplified by PCR using primers derived from consensus alpha-tubulin amino acid sequences. Both T. vaginalis alpha-tubulin sequences showed high identity to those described in other parabasalids (94.4%-97.3%), and exhibited a high degree of similarity to sequences from Metazoa (such as pig brain) and diplomonads (such as Giardia). Despite large evolutionary distances previously observed between trichomonads and mammals, the three-dimensional model of the T. vaginalis tubulin dimer was very similar to that of pig brain. Possible correlations between alpha-tubulin sequences and posttranslational modifications (PTMs) were examined. Our observations corroborated previous data obtained in T. vaginalis using specific anti-PTMs antibodies. As described in the related species Tritrichomonas mobilensis, microtubules are likely acetylated, non-tyrosinated, glutamylated, and non-glycylated in T. vaginalis. Evolutionary considerations concerning the time of appearance of these tubulin PTMs are also discussed since trichomonads are potentially one of the earliest diverging eukaryotic lineages.
我们已经在早期分化的真核生物阴道毛滴虫中分离并分析了一个编码α-微管蛋白的基因（atub1）。完整的atub1开放阅读框包含1356个碱基对，编码一个由452个氨基酸残基组成的多肽。使用源自共有α-微管蛋白氨基酸序列的引物，通过PCR扩增出了第二个α-微管蛋白基因（atub2）。阴道毛滴虫的两个α-微管蛋白序列与其他副基类生物中描述的序列具有高度同一性（94.4%-97.3%），并且与后生动物（如猪脑）和双滴虫（如贾第虫）的序列表现出高度相似性。尽管先前观察到毛滴虫与哺乳动物之间存在很大的进化距离，但阴道毛滴虫微管蛋白二聚体的三维模型与猪脑的非常相似。我们研究了α-微管蛋白序列与翻译后修饰（PTM）之间可能的相关性。我们的观察结果证实了先前在阴道毛滴虫中使用特异性抗PTM抗体获得的数据。正如在相关物种活跃三毛滴虫中所描述的那样，微管在阴道毛滴虫中可能被乙酰化、非酪氨酸化、谷氨酰胺化且非糖基化。由于毛滴虫可能是最早分化的真核生物谱系之一，因此还讨论了关于这些微管蛋白PTM出现时间的进化考量。
