Anatomical distributional defects in mutant genes associated with dominant intermediate Charcot-Marie-Tooth disease type C in an adenovirus-mediated mouse model

SeoJin Lee; Sandesh Panthi; Hyun Woo Jo; Jaeyoung Cho; Min-Sik Kim; Na Young Jeong; In Ok Song; Junyang Jung; Youngbuhm Huh

doi:10.4103/1673-5374.202920

Anatomical distributional defects in mutant genes associated with dominant intermediate Charcot-Marie-Tooth disease type C in an adenovirus-mediated mouse model

Neural Regen Res. 2017 Mar;12(3):486-492. doi: 10.4103/1673-5374.202920.

Authors

SeoJin Lee¹, Sandesh Panthi¹, Hyun Woo Jo¹, Jaeyoung Cho², Min-Sik Kim³, Na Young Jeong⁴, In Ok Song⁵, Junyang Jung^{1

2

6}, Youngbuhm Huh^{1

2

6}

Affiliations

¹ Department of Biomedical Science, Graduate School, Kyung Hee University, Dongdaemun-gu, Seoul, Korea.
² Department of Medicine, Graduate School, Kyung Hee University, Dongdaemun-gu, Seoul, Korea.
³ Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin-si, Gyeonggi-do, Korea.
⁴ Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Seo-gu, Busan, Korea.
⁵ Department of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Cheil General Hospital, Dankook University College of Medicine, Jung-gu, Seoul, Korea.
⁶ Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, Dongdaemun-gu, Seoul, Korea.

Abstract

Dominant intermediate Charcot-Marie-Tooth disease type C (DI-CMTC) is a dominantly inherited neuropathy that has been classified primarily based on motor conduction velocity tests but is now known to involve axonal and demyelination features. DI-CMTC is linked to tyrosyl-tRNA synthetase (YARS)-associated neuropathies, which are caused by E196K and G41R missense mutations and a single de novo deletion (153-156delVKQV). It is well-established that these YARS mutations induce neuronal dysfunction, morphological symptoms involving axonal degeneration, and impaired motor performance. The present study is the first to describe a novel mouse model of YARS-mutation-induced neuropathy involving a neuron-specific promoter with a deleted mitochondrial targeting sequence that inhibits the expression of YARS protein in the mitochondria. An adenovirus vector system and in vivo techniques were utilized to express YARS fusion proteins with a Flag-tag in the spinal cord, peripheral axons, and dorsal root ganglia. Following transfection of YARS-expressing viruses, the distributions of wild-type (WT) YARS and E196K mutant proteins were compared in all expressed regions; G41R was not expressed. The proportion of Flag/green fluorescent protein (GFP) double-positive signaling in the E196K mutant-type mice did not significantly differ from that of WT mice in dorsal root ganglion neurons. All adenovirus genes, and even the empty vector without the YARS gene, exhibited GFP-positive signaling in the ventral horn of the spinal cord because GFP in an adenovirus vector is driven by a cytomegalovirus promoter. The present study demonstrated that anatomical differences in tissue can lead to dissimilar expressions of YARS genes. Thus, use of this novel animal model will provide data regarding distributional defects between mutant and WT genes in neurons, the DI-CMTC phenotype, and potential treatment approaches for this disease.

Keywords: Charcot-Marie-Tooth Disease; YARS mutation; YARS-associated neuropathy; adenoviral vector-mediated mouse models; nerve regeneration; neural regeneration; tyrosyl-tRNA synthetase.