Formation of amyloid-like fibrils in COS cells overexpressing part of the Alzheimer amyloid protein precursor.
A pathological hallmark of Alzheimer's disease is the deposition of amyloid fibrils in the brain. The principal component of the amyloid fibril is beta/A4 protein, which is derived from a large membrane-bound glycoprotein, Alzheimer amyloid protein precursor (APP). Although the deposition of amyloid is thought to result from the aberrant processing of APP, the detailed molecular mechanisms of amyloidogenesis remain unclear. A C-terminal fragment of APP which spans the beta/A4 and cytoplasmic domains has a tendency to self-aggregate. In an attempt to establish a cultured-cell model for amyloid fibril formation, we have transfected COS-1 cells with complementary DNA encoding the C-terminal 100 residues of APP. In the perinuclear regions of a small population of DNA-transfected cells, we observed inclusion-like deposits which showed a strong immunohistochemical reaction towards an anti-C-terminal APP antibody or an anti-beta/A4 amyloid core-specific antibody. Electron microscope observations of the inclusion-carrying cells revealed an accumulation of amyloid-like fibrils of 8-22 nm diameter near and on the nuclear membrane. The fibrils showed a beaded or helical structure, and reacted positively with the anti-C-terminus antibody by immunoelectron microscopy. These results suggest that the formation of amyloid fibrils is an inherent characteristic of the C-terminal peptide of APP. The present system provides a suitable model for the molecular dissection of the process of brain amyloidogenesis.
Maruyama
K
K
Department of Molecular Biology, Psychiatric Research Institute of Tokyo, Japan.
Terakado
K
K
Usami
M
M
Yoshikawa
K
K
D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000235:genetics* / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D015870:Gene Expression; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000378:metabolism; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics*; D014162:Transfection
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011498:Protein Precursors; D004247:DNA