Bipolar spindle frequency and genome content are inversely regulated by the activity of two N-type kinesins in Entamoeba histolytica
Bipolar spindle frequency and genome content are inversely regulated by the activity of two N-type kinesins in Entamoeba histolytica
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DOI：
10.1111/j.1462-5822.2008.01150.x
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发表时间：
2008-07-01
影响因子：
3.4
通讯作者：
Lohia, Anuradha
中科院分区：
文献类型：
--
作者：
Dastidar, Promita Ghosh;Lohia, Anuradha
在溶组织内阿米巴滋养体中，双极微管纺锤体很少见，而单极或放射状微管集合体很常见。此外，在无菌培养的阿米巴细胞中发现了核DNA含量和多核的异质性。综上所述，这些观察表明，这些细胞中的基因组分离是不规则的。为了确定参与调节基因组分离的蛋白质，我们重点研究了影响双极有丝分裂纺锤体稳定性的动蛋白马达蛋白的组织溶解E.Organolytica同源物。我们早些时候已经证明，Kinesin-Eh Klp5-水平的增加导致了双极纺锤体频率的增加，同时基因组内容的异质性降低，表明在组织裂殖吸虫中，双极纺锤体频率与基因组内容呈负相关。在这项研究中，我们研究了Eh KlpA1，2-4在调节双极纺锤体频率和基因组含量中的作用。Eh Klp3、4和A1的表达下调没有影响，而Eh Klp2的下调导致双极纺锤体的频率增加和基因组内容的均质化，这与Eh Klp5表达增加的效果相似。除了微管外，Eh Klp2-4还与细胞质中的F-肌动蛋白结合，表明这些运动蛋白具有多功能。
Bipolar microtubular spindles are seen infrequently in Entamoeba histolytica trophozoites while monopolar or radial microtubular assemblies are common. Additionally, heterogeneity in nuclear DNA content and multi-nucleation is found in amoeba cells growing in axenic culture. Taken together these observations indicate that genome segregation is irregular in these cells. In order to identify proteins involved in regulating genome segregation, we have focused on studying E. histolytica homologues of kinesin motor proteins that are known to affect stability of bipolar mitotic spindles. We have demonstrated earlier that increased levels of the kinesin - Eh Klp5 - led to increased frequency of bipolar spindles accompanied with a reduction in the heterogeneity of genome content, showing that bipolar spindle frequency was inversely linked to genome content in E. histolytica. In this study, we have investigated the role of E. histolytica kinesins (Eh KlpA1, 2-4) in regulating bipolar spindle frequency and genome content. While downregulation of Eh Klp3, 4 and A1 showed no effect, downregulation of Eh Klp2 led to increased frequency of bipolar spindles and homogenization of genome content, similar to the effect of increased expression of Eh Klp5. In addition to microtubules, Eh Klp2-4 associated with F-actin in the cytoplasm, suggesting that these kinesins are multi-functional.