Quantitative analysis of tau isoform transcripts in sporadic tauopathies.
A number of neurodegenerative diseases, including Alzheimer's disease (AD), are characterized by intraneuronal accumulation of the tau protein. Some forms of FTDP-17 are caused by mutations in the tau gene affecting exon 10 splicing. Therefore, dysregulation of tau pre-mRNA splicing may be a contributing factor to sporadic tauopathies. To address this question, we devised a real-time RT-PCR strategy based on the use of a single fluorogenic probe to evaluate the ratio between tau isoforms containing or lacking exon 10 (4R/3R ratio) in post-mortem brain samples. We found a two- to six-fold increase in the 4R/3R ratio in cases of FTDP-17 linked to a splice site mutation, hence confirming the validity of the strategy. The difference in the 4R/3R ratio in the superior temporal and superior frontal gyri between AD and control brains was not statistically significant. Similarly, there was no significant difference in the 4R/3R ratio between Pick's disease cases and controls, indicating that the predominance of tau3R protein in PiD reflects post-translational modifications of specific isoforms. This study indicates that post-translational events are likely to be the main factors controlling tau isoform composition in sporadic tauopathies and highlights the benefit of quantitative RT-PCR in the assessment of splicing abnormalities in tauopathies.
Connell
J W
JW
Department of Neuroscience, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
Rodriguez-Martin
T
T
Gibb
G M
GM
Kahn
N M
NM
Grierson
A J
AJ
Hanger
D P
DP
Revesz
T
T
Lantos
P L
PL
Anderton
B H
BH
Gallo
J-M
JM
D000368:Aged; D017398:Alternative Splicing / Q000235:genetics*; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D001483:Base Sequence / Q000235:genetics; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003704:Dementia / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D005091:Exons / Q000235:genetics; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D020774:Pick Disease of the Brain / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D011110:Polymorphism, Genetic / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000235:genetics; D022821:RNA Splice Sites / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D024801:Tauopathies / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D016875:tau Proteins / Q000235:genetics* / Q000378:metabolism
D020033:Protein Isoforms; D022821:RNA Splice Sites; D012333:RNA, Messenger; D016875:tau Proteins