γ-羧基戊烯二酸内酯脱羧酶：原虫阴道毛滴虫中一种新型细胞周期相关的基底体蛋白。

γ-Carboxymuconolactone decarboxylase: a novel cell cycle-related basal body protein in the early branching eukaryote Trichomonas vaginalis.

机构信息

Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kweishan, Taoyuan, Taiwan.

Molecular Regulation and Bioinformatics Laboratory, Department of Parasitology, College of Medicine, Chang Gung University, Kweishan, Taoyuan, Taiwan.

出版信息

Parasit Vectors. 2017 Sep 26;10(1):443. doi: 10.1186/s13071-017-2381-4.

DOI:10.1186/s13071-017-2381-4

PMID:28950916

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5615479/

Abstract

BACKGROUND

γ-Carboxymuconolactone decarboxylase (CMD) participates in the β-ketoadipate pathway, which catalyzes aromatic compounds to produce acetyl- or succinyl-CoA, in prokaryotes and yeast. Our previous study demonstrated that expression of a CMD homologue that contains two signatures (dualCMD) is negatively regulated by iron in Trichomonas vaginalis. However, we were not able to identify the components of the β-ketoadipate pathway in the parasite's genome. These observations prompted us to investigate the biological functions of this novel CMD homologue in T. vaginalis.

METHODS

The specific anti-TvCMD1 antibody was generated, and the expression of TvCMD1 in T. vaginalis cultured under iron-rich and iron-deficient were evaluated. Phylogenetic, metabolomic and substrate induction (protocatechuate and benzoate) analysis were conducted to clarify the function of dualCMD in trichomonad cells. Subcellular localization of TvCMD1 was observed by confocal microscopy. The cell cycle-related role of TvCMD1 was assessed by treating cells with G2/M inhibitor nocodazole.

RESULTS

We confirmed that T. vaginalis is not able to catabolize the aromatic compounds benzoate and protocatechuate, which are known substrates of the β-ketoadipate pathway. Using immunofluorescence microscopy, we found that TvCMD1 is spatially associated with the basal body, a part of the cytoskeletal organizing center in T. vaginalis. TvCMD1 accumulated upon treatment with the G2/M inhibitor nocodazole. Additionally, TvCMD1 was expressed and transported to/from the basal body during cytokinesis, suggesting that TvCMD1 plays a role in cell division.

CONCLUSION

We demonstrated that TvCMD1 is unlikely to participate in the β-ketoadipate pathway and demonstrated that it is a novel basal body-localizing (associated) protein. This model sheds light on the importance of genes that are acquired laterally in the coevolution of ancient protists, which surprisingly functions in cell cycle regulation of T. vaginalis.

摘要

背景

γ-羧基戊烯二酮脱羧酶（CMD）参与β-酮己二酸途径，该途径在原核生物和酵母中催化芳香族化合物生成乙酰辅酶 A 或琥珀酰辅酶 A。我们之前的研究表明，一种含有两个特征（双 CMD）的 CMD 同源物的表达受阴道毛滴虫中铁的负调控。然而，我们无法在寄生虫的基因组中鉴定出β-酮己二酸途径的成分。这些观察结果促使我们研究这种新型 CMD 同源物在阴道毛滴虫中的生物学功能。

方法

生成了特异性的抗 TvCMD1 抗体，并评估了在富含铁和缺铁的条件下培养的阴道毛滴虫中 TvCMD1 的表达。进行了系统发育、代谢组学和底物诱导（原儿茶酸和苯甲酸）分析，以阐明双 CMD 在毛滴虫细胞中的功能。通过共聚焦显微镜观察 TvCMD1 的亚细胞定位。用 G2/M 抑制剂诺考达唑处理细胞，评估 TvCMD1 与细胞周期的关系。

结果

我们证实阴道毛滴虫不能代谢芳香族化合物苯甲酸和原儿茶酸，它们是β-酮己二酸途径的已知底物。使用免疫荧光显微镜，我们发现 TvCMD1 与基体外层（T. vaginalis 细胞骨架组织中心的一部分）在空间上相关。用 G2/M 抑制剂诺考达唑处理后，TvCMD1 积累。此外，TvCMD1 在有丝分裂期间表达并从基体外层运输到基体外层/从基体外层运输，表明 TvCMD1 在细胞分裂中发挥作用。