Characterization of huntingtin pathologic fragments in human Huntington disease, transgenic mice, and cell models.
Huntington disease (HD) is caused by the expansion of a glutamine (Q) repeat near the N terminus of huntingtin (htt), resulting in altered conformation of the mutant protein to produce, most prominently in brain neurons, nuclear and cytoplasmic inclusion pathology. The inclusions and associated diffuse accumulation of mutant htt in nuclei are composed of N-terminal fragments of mutant protein. Here, we used a panel of peptide antibodies to characterize the htt protein pathologies in brain tissues from human HD, and a transgenic mouse model created by expressing the first 171 amino acids of human htt with 82Q (htt-N171-82Q). In tissues from both sources, htt pathologic features in nuclei were detected by antibodies to htt peptides 1-17 and 81-90 but not 115-129 (wild-type huntingtin numbering with 23 repeats). Human HEK 293 cells transfected with expression vectors that encode either the N-terminal 233 amino acids of human htt (htt-N233-82Q) or htt-N171-18Q accumulated smaller N-terminal fragments with antibody-binding characteristics identical to those of pathologic peptides. We conclude that the mutant htt peptides that accumulate in pathologic structures of human HD and httN171-82Q in mice are produced by similar, yet to be defined, proteolytic events in a region of the protein near or within amino acids 90-115.
Schilling
Gabriele
G
Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Klevytska
Alexandra
A
Tebbenkamp
Andrew T N
AT
Juenemann
Katrin
K
Cooper
Jillian
J
Gonzales
Victoria
V
Slunt
Hilda
H
Poirer
Michelle
M
Ross
Christopher A
CA
Borchelt
David R
DR
D000293:Adolescent; D000328:Adult; D000818:Animals; D002460:Cell Line; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011180:Postmortem Changes; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection / Q000379:methods
D010446:Peptide Fragments; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins