Takano-Rojas Harumi, Zickler Denise, Peraza-Reyes Leonardo
Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México DF, Mexico.
Univ. Paris-Sud, CNRS UMR8621, Institut de Génétique et Microbiologie, 91405 Orsay, France.
Mycologia. 2016 May-Jun;108(3):590-602. doi: 10.3852/15-112. Epub 2016 Feb 23.
Peroxisomes are versatile and dynamic organelles that are required for the development of diverse eukaryotic organisms. We demonstrated previously that in the fungus Podospora anserina different peroxisomal functions are required at distinct stages of sexual development, including the initiation and progression of meiocyte (ascus) development and the differentiation and germination of sexual spores (ascospores). Peroxisome assembly during these processes relies on the differential activity of the protein machinery that drives the import of proteins into the organelle, indicating a complex developmental regulation of peroxisome formation and activity. Here we demonstrate that peroxisome dynamics is also highly regulated during development. We show that peroxisomes in P. anserina are highly dynamic and respond to metabolic and environmental cues by undergoing changes in size, morphology and number. In addition, peroxisomes of vegetative and sexual cell types are structurally different. During sexual development peroxisome number increases at two stages: at early ascus differentiation and during ascospore formation. These processes are accompanied by changes in peroxisome structure and distribution, which include a cell-polarized concentration of peroxisomes at the beginning of ascus development, as well as a morphological transition from predominantly spherical to elongated shapes at the end of the first meiotic division. Further, the mostly tubular peroxisomes present from second meiotic division to early ascospore formation again become rounded during ascospore differentiation. Ultimately the number of peroxisomes dramatically decreases upon ascospore maturation. Our results reveal a precise regulation of peroxisome dynamics during sexual development and suggest that peroxisome constitution and function during development is defined by the coordinated regulation of the proteins that control peroxisome assembly and dynamics.
过氧化物酶体是多功能且动态变化的细胞器，对于多种真核生物的发育至关重要。我们之前已证明，在真菌嗜热栖热放线菌中，有性发育的不同阶段需要不同的过氧化物酶体功能，包括减数分裂细胞（子囊）发育的起始和进程以及有性孢子（子囊孢子）的分化和萌发。这些过程中的过氧化物酶体组装依赖于驱动蛋白质导入该细胞器的蛋白质机制的差异活性，这表明过氧化物酶体形成和活性受到复杂的发育调控。在此我们证明，过氧化物酶体动态变化在发育过程中也受到高度调控。我们发现嗜热栖热放线菌中的过氧化物酶体具有高度动态性，并通过大小、形态和数量的变化来响应代谢和环境线索。此外，营养细胞和有性细胞类型的过氧化物酶体在结构上有所不同。在有性发育过程中，过氧化物酶体数量在两个阶段增加：在子囊早期分化阶段和子囊孢子形成期间。这些过程伴随着过氧化物酶体结构和分布变化，包括在子囊发育开始时过氧化物酶体在细胞两极的聚集，以及在第一次减数分裂末期从主要球形到细长形的形态转变。此外，从第二次减数分裂到子囊孢子形成早期存在的大多为管状的过氧化物酶体在子囊孢子分化期间再次变圆。最终，在子囊孢子成熟时过氧化物酶体数量急剧减少。我们的结果揭示了有性发育过程中过氧化物酶体动态变化的精确调控，并表明发育过程中过氧化物酶体的组成和功能是由控制过氧化物酶体组装和动态变化的蛋白质的协同调控所定义的。
