Role of the Cytosolic Heat Shock Protein 70 Ssa5 in the Ciliate Protozoan Tetrahymena thermophila
Role of the Cytosolic Heat Shock Protein 70 Ssa5 in the Ciliate Protozoan Tetrahymena thermophila
复制标题
DOI：
10.1111/jeu.12203
复制
发表时间：
2015-07-01
影响因子：
2.2
通讯作者：
Pearlman, Ronald E.
中科院分区：
文献类型：
--
作者：
Fukuda, Yasuhiro;Akematsu, Takahiko;Pearlman, Ronald E.
热休克蛋白70（Heat shock protein 70，Hsp70）是一个保守的分子伴侣蛋白家族，其功能在许多模式生物中已得到充分研究。在这里，我们专注于一个热休克蛋白70称为Ssa 5的纤毛虫原生动物四膜虫嗜热，并揭示其翻译是热诱导的一般热休克蛋白。此外，该蛋白质在有性生殖（接合）期间以及响应于热应激时在细胞质中大量表达。敲除SSA5（SSA5）不会影响细胞在热应激下的存活，这可能是由于其他Hsp70旁系同源物弥补了缺陷。在接合过程中，SSA5导致受精缺陷，其中两个原核非常接近但从不融合。未受精的原核分化，形成具有发育的单倍体胚系和体细胞核的异核体。此外，亲本体细胞核的退化不受影响。这些结果表明，Ssa 5在原核融合和受精的具体参与。
Heat shock protein 70 (Hsp70) is a member of a family of conserved chaperone proteins whose function is well investigated in many model organisms. Here we focus on an Hsp70 called Ssa5 in the ciliate protozoan Tetrahymena thermophila, and reveal that its translation is heat inducible as for general Hsps. Moreover, the protein is abundantly expressed in the cytoplasm during sexual reproduction (conjugation) as well as in response to heat-stress. Knocking out of SSA5 (SSA5) does not affect the survival of the cell under heat-stress, likely due to other Hsp70 paralogs compensating for the defect. During conjugation, SSA5 leads to a fertilization defect in which the two pronuclei are in close proximity but never fuse. The unfertilized pronuclei differentiate, resulting in a heterokaryon with developed haploid germline and somatic nuclei. In addition, degeneration of the parental somatic nucleus is not affected. These results suggest a specific involvement of Ssa5 in pronuclear fusion and fertilization.