Contributions of selective knockout studies to understanding cholinesterase disposition and function

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• The acetylcholinesterase (AChE) gene in mammals is subject to alternative splicing, leading to diverse protein functions.
• Previous studies in Drosophila suggested complete gene deletion would be lethal, but mouse models show a different outcome.

Purpose of the Study:

• To investigate the functional roles of alternatively spliced exons in AChE tissue distribution and activity.
• To understand the impact of specific gene deletions on AChE function in vivo.

Main Methods:

• Generation of transgenic mouse strains with targeted deletions of AChE exons 5, 6, or both.
• Creation of knockout strains for AChE anchoring proteins PRiMA and ColQ.
• Development of a knockout mouse with a deletion in an upstream intronic regulatory region controlling AChE expression.

Main Results:

• Deletion of exon 6 significantly reduced brain (93%) and muscle (72%) AChE levels.
• Deletion of exon 5 eliminated AChE from red blood cells and platelet surfaces.
• Intronic regulatory region deletion primarily affected muscle and platelet surface AChE.

Conclusions:

• Alternative splicing of the AChE gene is crucial for its tissue-specific localization and function in mammals.
• Targeted gene modifications in mice provide critical insights into AChE's in vivo roles, complementing in vitro studies.