Scrapie agent proteins do not accumulate in grey tremor mice

Area of Science:

• Neuroscience
• Genetics
• Pathology

Background:

• Grey tremor mice present with spongiform encephalopathy, neurological abnormalities, and early mortality.
• The disease shares similarities with transmissible spongiform encephalopathies like scrapie and Creutzfeldt-Jakob disease.
• Previous observations suggested a potential role for a scrapie-like agent due to transmissibility via inoculation.

Purpose of the Study:

• To investigate the presence of the mouse scrapie agent protein (MoSp33-37) and its normal cellular homologue in grey tremor mouse brains.
• To determine if the scrapie agent is involved in the pathogenesis of grey tremor disease.

Main Methods:

• Immunoblot analysis of brain homogenates from grey tremor mice, scrapie-affected mice, and normal mice.
• Protease treatment of homogenates to detect the abnormal prion protein isoform.
• Prion protein purification and concentration methods.

Main Results:

• Both normal and abnormal prion protein isoforms were detected in untreated homogenates.
• Protease-treated grey tremor mouse brain homogenates showed no detectable MoSp33-37.
• MoSp33-37 was concentrated in scrapie-affected mice but not detected in grey tremor or normal mice.

Conclusions:

• The absence of detectable MoSp33-37 in grey tremor mouse brains strongly suggests that the scrapie agent is not the cause of this disease.
• Grey tremor disease represents a distinct form of spongiform encephalopathy not mediated by the known scrapie agent.
• Further research is needed to elucidate the specific genetic or infectious cause of grey tremor disease.