Cell into which protein, which can serve as polymerization nucleus of protein polymer, or polymer thereof is introduced, and method for production of the cell

A method for producing a cellular model of α-synuclein inclusion formation by polymerization, wherein the method comprises:

• introducing into a neuron or a glial cell, by use of a lipid transport reagent, an α-synuclein fibril formed from α-synuclein of SEQ ID NO:
• 2 or a mutant thereof at A30P, A53T, or E46K or a variant thereof with portion(s) deleted in any or all of the amino acid residues at positions 10 to 15, 21 to 26, 32 to 37, 43 to 48, and 58 to 63, said α-synuclein fibril being a suitable polymerization nucleus of filamentous α-synuclein inclusions;
• introducing into a neuron or a glial cell an expression vector encoding a recombinant α-synuclein of SEQ ID NO:
• 2 or a mutant thereof at A30P, A53T, or E46K or a variant thereof with portion(s) deleted in any or all of the amino acid residues at positions 10 to 15, 21 to 26, 32 to 37, 43 to 48, and 58 to 63;
• and
• thereby causing interaction between the α-synuclein fibril and the recombinant α-synuclein generated by expression of the vector forming filamentous α-synuclein inclusions in the cell by polymerization,
• wherein the α-synuclein fibril which can serve as a polymerization nucleus and the recombinant α-synuclein generated in the cell are phosphorylated in the cell.