Giardia lamblia expresses a proteobacterial-like DnaK homolog
Giardia lamblia expresses a proteobacterial-like DnaK homolog
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DOI：
10.1093/oxfordjournals.molbev.a003832
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发表时间：
2001-04-01
影响因子：
10.7
通讯作者：
Sogin, ML
中科院分区：
文献类型：
--
作者：
Morrison, HG;Roger, AJ;Sogin, ML
我们在蓝氏贾第鞭毛虫线粒体寄生虫中发现了一个编码分子伴侣蛋白HSP70的新基因。预测的蛋白与细菌DnaK和线粒体hsp70相似。该基因在滋养体生长和成囊过程中以恒定水平转录和翻译。序列与细胞质内质网（ER）数据集的比对。线粒体和DnaK的HSP70同源物表明，该序列具有极大的差异，并且包含gi心包HSP70特有的插入。系统发育分析表明，该序列与细胞质和内质网形式不同，与变形菌和线粒体DnaKs最相似。然而，与cpn60的类似分析相比，该数据集的系统发育分析并没有强有力地支持α变形菌和线粒体序列之间的特定关系。这些数据既没有证实也没有拒绝这种基因是线粒体二次丢失的遗迹的可能性；它们留下了在单独的内共生事件中获得的可能性。
We identified a novel gene encoding molecular chaperone HSP70 in the amitochondriate parasite Giardia lamblia. The predicted protein is similar to bacterial DnaK and mitochondrial HSP70s. The gene is transcribed and translated at a constant level during trophozoite growth and encystation. Alignment of the sequence with a data set of cytosolic, endoplasmic reticulum (ER). mitochondrial, and DnaK HSP70 homologs indicated that the sequence was extremely divergent and contained insertions unique to giardial HSP70s. Phylogenetic analyses demonstrated that this sequence was distinct from the cytosolic and ER forms and was most similar to proteobacterial and mitochondrial DnaKs. However, a specific relationship with the alpha proteobacterial and mitochondrial sequences was not strongly supported by phylogenetic analyses of this data set, in contrast to similar analyses of cpn60. These data neither confirm nor reject the possibility that this gene is a relic of secondary mitochondrial loss; they leave open the possibility that it was acquired in a separate endosymbiotic event.