A024 Investigating the role of the Huntingtin ubiquitination sites K6 and K9 in a novel mouse model of Huntington disease
Year: 2024
Type: conference-paper
Abstract: Background Lysine residues 6 and 9 in the exon1 of N-terminal mutant huntingtin (mHtt) were identified to be highly ubiquitinated in BACHD rats brain tissue samples. Overexpressing mHtt exon 1 lacking these ubiquitination sites in primary rat cortical neurons and HEK293 cells was found to reduce the formation rates and size of aggregates in time-lapse microscopy, but increase smaller and less visible aggregate numbers, while reduce soluble mHtt protein levels. Additionally, these site mutations were associated with elevated cell death.1 However, the in vivo effects of these ubiquitination site mutations remain unexplored. Aims To investigate the role of the huntingtin ubiquitination sites K6 and K9 in the pathogenesis of Huntington’s disease in vivo. Methods/Techniques Knock-in (KI) mice were generated by microinjection of targeted embryonic stem cells (ESCs) into blastocysts. The ESCs were genetically manipulated to bear human mHtt exon1 containing 134 CAG repeats, with or without mutations at K6 and K9 coding sites. Mice genotype was identified using Sanger sequencing. Protein expression of mHtt in mice was detected via immunoblotting. Results Site mutations were confirmed via sanger sequencing in genomic DNA of both mouse line. At 4 weeks of age, there were no significant differences between the two lines in terms of body weight, brain weight, and HTT expression levels. Conclusions We have developed a new KI mouse model comprising two lines that differ only at lysine residues K6 and K9 in human htt exon 1. There was no significant difference in phenotype at 4 weeks. This mouse model will be further characterized using behavioral, neuropathological, biochemical and brain imaging methods. We expect that these mice will be a useful tool to investigate the implications of mHtt ubiquitination in vivo. Reference Hakim-Eshed V, Boulos A, Cohen-Rosenzweig C, Yu-Taeger L, Ziv T, Kwon YT, Riess O, Phuc Nguyen HH, Ziv NE, Ciechanover A. Site-specific ubiquitination of pathogenic huntingtin attenuates its deleterious effects. Proc Natl Acad Sci U S A 2020 Aug 4;117(31):18661-18669.
Authors: Pengfei Qi, Libo Yu-Täger, Huu Phuc Nguyen, Noam E Ziv, Aaron Ciechanover
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W4402374072