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Tissue transglutaminase contributes to disease progression in the R6/2 Huntington's disease mouse model via aggregate‐independent mechanisms
Author(s) -
Bailey Craig D. C.,
Johnson Gail V. W.
Publication year - 2005
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02839.x
Subject(s) - huntingtin , tissue transglutaminase , huntington's disease , huntingtin protein , gene knockout , knockout mouse , biology , striatum , microbiology and biotechnology , endocrinology , medicine , disease , gene , genetics , biochemistry , dopamine , enzyme
Huntington's disease (HD) is caused by an expansion of CAG repeats within the huntingtin gene and is characterized by intraneuronal mutant huntingtin protein aggregates. In order to determine the role of tissue transglutaminase (tTG) in HD aggregate formation and disease progression, we cross‐bred the R6/2 HD mouse model with a tTG knockout mouse line. R6/2 mice that were tTG heterozygous knockouts (R6/2 : tTG+/–) and tTG homozygous knockouts (R6/2 : tTG–/–) showed a very similar increase in aggregate number within the striatum compared with R6/2 mice that were wild‐type with respect to tTG (R6/2 : tTG+/+). Interestingly, a significant delay in the onset of motor dysfunction and death occurred in R6/2 : tTG–/– mice compared with both R6/2 : tTG+/+ and R6/2 : tTG+/– mice. As aggregate number was similarly increased in the striatum of both R6/2 : tTG+/– and R6/2 : tTG–/– mice, whereas only R6/2 : tTG–/– mice showed delayed disease progression, these data suggest that the contribution of tTG towards motor dysfunction and death in the R6/2 mouse is independent of its ability to negatively regulate aggregate formation. Moreover, the combined results from this study suggest that the formation of striatal huntingtin aggregates does not directly influence motor dysfunction or death in this HD mouse model.