Mitotic inheritance of endoplasmic reticulum in the primitive red alga Cyanidioschyzon merolae
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Endoplasmic reticulum (ER) is a major site for secretory protein folding and lipid synthesis. Since ER cannot be synthesized de novo, it must be inherited during the cell cycle. Studying ER inheritance can however be difficult because the ER of typical plant and animal cells is morphologically complex. Therefore, our study used Cyanidioschyzon merolae, a species that has a simple ER structure, to investigate the inheritance of this organelle. Using immunofluorescence microscopy, we demonstrated that C. merolae contains a nuclear ER (nuclear envelope) and a small amount of peripheral ER extending from the nuclear ER. During mitosis, the nuclear ER became dumbbell-shaped and underwent division. Peripheral ER formed ring-like structures during the G1 and S phases, and extended toward the mitochondria and cell division planes during the M phase. These observations indicated that C. merolae undergoes closed mitosis, whereby the nuclear ER does not diffuse, and the peripheral ER contains cell cycle-specific structures.
KeywordsER Inheritance Cyanidioschyzon
This work was supported by a Research Fellowship from the Japanese Society for the Promotion of Science (11044) to F.Y., a Grant for Scientific Research on Priority Areas (19207004) to T.K., the Frontier Project “Adaptation and Evolution of Extremophiles” from the Ministry of Education, Culture, Sports, Science and Technology of Japan, and a Grant-in-Aid to T.K. We have no financial relationship with the organization that sponsored this research.
Conflict of interest
The authors declare that they have no conflict of interest.
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