Coupling of posterior cytoskeletal morphogenesis to the G1/S transition in the Trypanosoma brucei cell cycle
Coupling of posterior cytoskeletal morphogenesis to the G1/S transition in the Trypanosoma brucei cell cycle
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DOI：
10.1091/mbc.e04-05-0368
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Wang, CC
中科院分区：
文献类型：
--
作者：
Tu, XM;Wang, CC
采用RNA干扰（RNAi）技术，对布氏锥虫前环型中4种Cdc 2相关激酶（CRK 1、2、4和6）的表达水平进行了研究。CRK 1和CRK 2的双敲低导致G1期细胞生长停滞，伴随着核DNA合成的明显停止。在先前的研究中，被阻滞的细胞在后端变得细长，就像通过敲低CycE 1/CYC 2产生的G1期细胞一样。然而，在目前的研究中，大约5%的G1期细胞也具有多分支的后端，这在T。布鲁塞。DAPI和免疫荧光染色显示，单个核，动基体，鞭毛在每个G1细胞的前部。分裂和严重延长的后端被酪氨酸化α-微管蛋白的抗体严重染色，表明新合成的微管的积累。一个显着的人口无核细胞（zoids），显然来自动质体支配的胞质分裂和细胞分裂的G1细胞，也延长和分支的后端充满了新合成的微管。G1细胞和zoids中微管的这种持续向后延伸表明CRK 1和CRK 2对G1/S通道和微管紧身衣向后端的有限生长施加协调控制。这种联系可能提供了一个新的见解，在其细胞周期进程中的古原生生物的形态维持的机制。
The expression levels of four Cdc2-related kinases (CRK1, 2, 4, and 6) in the procyclic form of Trypanosoma brucei were knocked down in pairs using the RNA interference (RNAi) technique. A double knockdown of CRK1 and CRK2 resulted in arrested cell growth in the G1 phase accompanied by an apparent cessation of nuclear DNA synthesis. The arrested cells became elongated at the posterior end like the G1-phase cells generated by knockdown of CycE1/CYC2 in a previous study. However, similar to5% of the G1 cells in the current study also possessed multiply branched posterior ends, which have not previously been observed in T. brucei. DAPI and immunofluorescence staining showed a single nucleus, kinetoplast, basal body, and flagellum in the anterior portion of each G1 cell. The split and grossly extended posterior ends were heavily stained with antibodies to tyrosinated alpha-tubulin, suggesting an accumulation of newly synthesized microtubules. A significant population of anucleate cells (zoids), apparently derived from kinetoplast-dictated cytokinesis and cell division of the G1 cells, also had extended and branched posterior ends filled with newly synthesized microtubules. This continued posterior extension of microtubules in the G1 cells and zoids suggests that CRK1 and CRK2 exert a coordinated control on G1/S passage and the limited growth of the microtubule corset toward the posterior end. This connection may provide a new insight into the mechanism of morphological maintenance of an ancient protist during its cell cycle progression.