Generation of transgenic marmosets using a tetracyclin-inducible transgene expression system as a neurodegenerative disease model†

Abstract

Controllable transgene expression systems are indispensable tools for the production of animal models of disease to investigate protein functions at defined periods. However, in nonhuman primates that share genetic, physiological, and morphological similarities with humans, genetic modification techniques have not been well established; therefore, the establishment of novel transgenic models with controllable transgene expression systems will be valuable tools to understand pathological mechanism of human disease. In the present study, we successfully generated transgenic marmosets using a tetracyclin-inducible transgene expression (tet-on) system as a neurodegenerative disease model. The mutant human ataxin 3 gene controlled by the tet-on system was introduced into marmoset embryos via lentiviral transduction, and 34 transgene-introduced embryos were transferred into the uteri of surrogate mothers. Seven live offspring (TET1-7) were obtained, of which four were transgenic. Fibroblasts from TET1 and 3 revealed that inducible transgene expression had occurred after treatment with 10 μg/mL of doxycycline, while treatment with doxycycline via drinking water resulted in 1.7- to 1.8-fold inducible transgene expression compared with before treatment. One transgenic second-generation offspring (TET3-3) was obtained from TET3, and doxycycline-inducible transgene expression in its fibroblasts showed that TET3-3 maintained a high transgene expression level that matched its parent. In conclusion, we established a novel transgenic marmoset line carrying the mutant human ataxin 3 gene controlled by the tet-on system. The development of nonhuman primate models with controllable transgene expression systems will be useful for the identification of disease biomarkers and evaluation of the efficacy and metabolic profiles of therapeutic candidates.

Generation of Common Marmoset Model Lines of Spinocerebellar Ataxia Type 3

“…It appears that although ubiquitously expressed promoters induce strong transgene expression, they also lead to clinically irrelevant symptoms. Therefore, in addition to previous SCA3 model marmosets whose transgenes were driven by the CMV promoter, we generated a transgenic marmoset model line of SCA3 in which transgenes were controlled by the Tet-inducible gene expression system (Tomioka et al, 2017b). The ability to control the disease onset is an important advantage in biomarker development studies because it allows us to define the disease onset at the molecular level.…”

Aging research using the common marmoset: Focus on aging interventions

“…Regarding aging research, many of the transgenic lines proposed and developed using marmosets have focused on neurologic disease and modeling of neurodegenerative disorders such as Alzheimer's and Parkinson's. Lentiviral transgenic induction of Tet-on human ataxin 3 genes has produced young marmosets with neurodegenerative disease phenotype [81,82]. Recently, marmosets that express transgenic induction of intracellular calcium indicators have been developed in order to greatly advance the technology and imaging possibilities [83].…”

Local transgene expression and whole‐body transgenesis to model brain diseases in nonhuman primate

“…Two offspring exhibited whole‐body expression of the EGFP reporter . Then, lentivirus was used to create transgenic marmoset and cynomolgus monkey models …”

“…The mutant human ataxin 3 gene controlled by the tet‐on system was injected into marmoset's embryos via lentiviral transduction. Four of the seven live offspring were transgenic and carried the transgene controlled by the tet‐on system . With the objective to monitor in vivo neural activity, Park et al reported the generation of a transgenic marmoset expressing GCaMP, a genetically encoded calcium indicator, under ubiquitous and neuronal promoters .…”