In order to clarify this discrepancy, we assessed the cleavage of this mutant in brain of transgenic mice expressing secPrPC in Prnp−/− mice [41].
Here we describe a highly sensitive time-resolved Förster resonance energy transfer (FRET) assay for quantification of soluble mutant huntingtin in brain, plasma, and cerebrospinal fluid.
Acridine orange staining showed that at 48 hpf, when wild-type embryos have very few apoptotic cells, such cells were abundant in mutants, especially in brains (Fig. 1D,E).
Finally, despite the apparent neurological or neuromuscular nature of the complication we found no clear morphological differences between mutants and controls in brain or muscle, suggesting that the defect is subtle and/or is physiologic rather than structural.
For example, expression of mutant huntingtin in brain-derived cells reduced the processing of the sterol response-element binding protein (SREBP; the master regulator of the cholesterol biosynthetic pathway) (Valenza et al., 2005).
APP23 mice over-express the FAD mutant human APP in brain, and develop amyloid plaques similar to the human pathology [8].
CC2D1A was previously shown to associate with PDE4D5 even in the CC2D1A mutant cells and in brain tissue [ 17].
They are also characterized by the presence of widespread nuclear inclusions of mutant polyQ-Htt in brain neurons.
Total Thr668Ala mAPP in knock-in mutant mouse brains was identical in levels and distribution except that, as expected, there was no detectable phospho-mAPP (Fig. 5).
These biological functions were not significantly activated in the mutant-infected brain; in contrast, many SDEG involved in the host protective responses were activated only in the mutant-infected mouse brain.
