Tomoyo Ochiishi, Senior Researcher, Brain Genetics Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Assistant Professor Akira Kitamura, Graduate School of Advanced Life Sciences, Hokkaido University, Hideki Shimura, Associate Professor, Department of Neurology, Juntendo University School of Medicine, etc. We have developed a technology to visualize the dynamics of amyloid β (Aβ) protein, which is one of the causative factors, in living nerve cells and in vivo.
Aβ easily polymerizes to form large aggregates.Green fluorescent protein (GFP) is often used for observing the localization of proteins in living cells and individuals, but the protein in which Aβ and GFP are fused (Aβ-GFP) is a protein obtained by polymerizing Aβ. It is said that fluorescence is inhibited.Therefore, even if it was expressed in vivo, fluorescence was not observed when Aβ was polymerized, and it was difficult to visualize the localization and dynamics of Aβ.
Until now, when 12 or less amino acids were used as the amino acid sequence (linker) connecting Aβ and GFP, the fluorescence of GFP disappeared when Aβ polymerized.This time, we have developed a fusion protein that uses 14 amino acids as a linker and can observe fluorescence regardless of the polymerization state of Aβ.It was found that this Aβ-GFP does not proceed beyond a certain level due to the fusion of GFP, and exists in the form of an oligomer centered on a dimer to the inside and outside of the living body.This makes it possible to analyze the dynamic movement of Aβ in living cells and the accumulation state in primary cultured neurons.In addition, since it forms highly toxic Aβ oligomers involved in the onset of Alzheimer's disease, it is possible to analyze the relationship between the degree of polymerization of Aβ oligomers and their toxicity to cells.
In the future, it is expected to contribute to the screening of candidate substances for Alzheimer's disease therapeutic agents using cultured cells and living individuals, and to the elucidation of the onset mechanism of Alzheimer's disease.
