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Updated: Aug 25, 2025

Efficient and Scalable Production of Full-length Human Huntingtin Variants in Mammalian Cells using a Transient Expression System
Published on: December 10, 2021
Differential expression and roles of Huntingtin and Huntingtin-associated protein 1 in the mouse and primate brains
Xingxing Chen1,2, Yize Sun2, Laiqiang Chen2
1Brain Science and Advanced Technology Institute, Wuhan University of Science and Technology, Wuhan, 430000, Hubei, China.
Huntingtin-associated protein 1 (HAP1) is the first identified protein whose function is affected by its abnormal interaction with mutant huntingtin (mHTT), which causes Huntington disease. However, the expression patterns of Hap1 and Htt in the rodent brain are not correlated. Here we found that the primate HAP1, unlike the rodent Hap1, is correlatively expressed with HTT in the primate brains. CRISPR/Cas9 targeting revealed that HAP1 deficiency in the developing human neurons did not affect neuronal differentiation and gene expression as seen in the mouse neurons. However, deletion of HAP1 exacerbated neurotoxicity of mutant HTT in the organotypic brain slices of adult monkeys. These findings demonstrate differential HAP1 expression and function in the mouse and primate brains, and suggest that interaction of HAP1 with mutant HTT may be involved in mutant HTT-mediated neurotoxicity in adult primate neurons.
Huntingtin-associated protein 1 (HAP1) is the first identified protein whose function is affected by its abnormal interaction with mutant huntingtin (mHTT), which causes Huntington disease. However, the expression patterns of Hap1 and Htt in the rodent brain are not correlated. Here we found that the primate HAP1, unlike the rodent Hap1, is correlatively expressed with HTT in the primate brains. CRISPR/Cas9 targeting revealed that HAP1 deficiency in the developing human neurons did not affect neuronal differentiation and gene expression as seen in the mouse neurons. However, deletion of HAP1 exacerbated neurotoxicity of mutant HTT in the organotypic brain slices of adult monkeys. These findings demonstrate differential HAP1 expression and function in the mouse and primate brains, and suggest that interaction of HAP1 with mutant HTT may be involved in mutant HTT-mediated neurotoxicity in adult primate neurons.

