促进染色质转录因子亚基Pob3调控嗜热四膜虫有性生殖过程  

Facilitate Chromatin Transcription Complex Subunit Pob3 Regulates Sexual Reproduction in Tetrahymena thermophila

作　　者：陈虹宇 许静 薄涛[1] 连荫杰 郝惠娟 王伟 CHEN Hongyu;XU Jing;BO Tao;LIAN Yinjie;HAO Huijuan;WANG Wei(Key Laboratory of Chemical Biology and Molecular Engineering of Ministryof Education,Institute of Biotechnology,Shanxi University,Taiyuan 030006,China;College of Life Sciences,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学生物技术研究所,化学生物学与分子工程教育部重点实验室,太原030006 [2]山西大学生命科学学院,太原030006

出　　处：《中国细胞生物学学报》2020年第4期582-591,共10页Chinese Journal of Cell Biology

基　　金：国家自然科学基金项目(批准号:31872224,31471999);山西省自然科学基金(批准号:201901D111008)资助的课题。

摘　　要：促进染色质转录因子(facilitate chromatin transcription,FACT)在DNA复制、转录、损伤修复相关的染色质重塑过程发挥重要的作用。FACT复合物包含POB3/SSRP1(structure-specific recognition protein-1)和SPT16(suppressor of Ty 16)两个亚基,该复合物及其亚基的功能虽在真菌、植物和动物上有些研究,但具体功能仍不完全清楚。该文以原生动物四膜虫为研究对象,对其促进染色质转录因子亚基Pob3进行研究。结果显示,嗜热四膜虫FACT复合物中的POB3基因在营养生殖时期和饥饿时期表达,在有性生殖时期表达上调。在生长期和饥饿期,Pob3定位于亲本大核和小核上;在有性生殖时期,Pob3定位于功能小核和新大核,在降解的小核和降解的亲本大核中定位消失。截短N-端的HA-Pob3Δ33在有性生殖前期定位在细胞质,但在有性生殖后期定位在配子和新发育的大核。截短C-端的HA-Pob3Δ87只定位在细胞质。POB3敲减突变株发生了异常的配子核和合子核的有丝分裂,导致有性生殖无法正常完成。结果表明,促进染色质转录因子亚基Pob3参与调控嗜热四膜虫细胞核的有丝分裂,对有性生殖的完成是必需的。The FACT(facilitate chromatin transcription)complex is involved in chromatin remodeling during transcription,replication,and DNA repair.FACT contains two subunits:POB3/SSRP1(structure-specific recognition protein-1)and SPT16(suppressor of Ty 16).Although the function of the complex has been studied in fungi,plants,and animals,it′s function is not completely clear.Tetrahymena thermophila contains two different nucleus and changes chromatin structure during sexual development stage.In the study,we found POB3 expressed at a lower level in the vegetative growth stage and starvation stage,and highly expressed throughout conjugation stage in T.thermophila.HA-Pob3 localized in the parental macronucleus and micronucleus during the growth and starvation stage and localized in the new macronuclei and micronuclei during sexual developmental stage.Micronuclear stainning was stronger than macronuclear signal through sexual developmental stage.Truncated HA-Pob3Δ33 localized in the cytoplasm in the early sexual reproduction,but occurred in the selected gametic nuclei and new macronuclei in the late sexual reproduction.Truncated HA-Pob3Δ87 localized only in the cytoplasm throughout sexual reproduction stage.POB3 knockdown mutants failed to complete gametic mitosis and zygotic mitosis,which aborted sexual reproduction progress.The results showed that Pob3 regulated nuclear mitosis and was required for normal sexual reproduction progress in T.thermophila.

关 键 词：嗜热四膜虫 Pob3 细胞定位 突变 有性生殖 

分 类 号：Q75[生物学—分子生物学]