Molecular mechanism of cerebellum-dependent motor learning deficits in Kdm3b mutant mouse

Cerebellum;Histone modification;Demethylase;OKR;Kdm3b;Flocculus;610.72

의과대학 의과학과 ;

University:서울대학교 대학원

关键词: Cerebellum;    Histone modification;    Demethylase;    OKR;    Kdm3b;    Flocculus;    610.72;   

Others  :  http://s-space.snu.ac.kr/bitstream/10371/161543/1/000000156819.pdf

美国|英语

来源: Seoul National University Open Repository

【 摘 要 】

The chromatin remodeling through an epigenetic modification is the fundamental genetic modification through which an individual can adjust to the environmental changes. Histone modification is one of the genetic modifications which modulated by histone methylases and demethylases. Lysine demethylase 3B (KDM3B) is one of the demethylases whole target site is H3K9me2. Cerebellum-dependent motor learning increases H3K9me2 level in the flocculus of wild-type mice. For this purpose, we created Kdm3b Het mice to study the function of KDM3B, and its target H3K9me2. Cerebellum-dependent motor learning including OKR increase and VOR increase showed deficits in Kdm3b Het mice. In order to confirm these mice having less KDM3B protein amount, immunoblotting analysis was proceeded. Less KDM3B was detected in the flocculus and vermis of Kdm3b Het mice compared to wild-type mice. We tested whether this reduced KDM3B amount affects the level of H3K9me2 in the flocculus of cerebellum. However, whole flocculus did not show increased level. Immunohistochemistry indicated that H3K9me2 was expressed in the granule cell layer of the cerebellum vermis specifically. This brain region from Kdm3b Het mice was precisely microdissected and immunoblot was performed, showing significantly increased H3K9me2 level in the granule cell, but not in Purkinje cell layer. Granule cell layer of wild-type and Kdm3b Het mice were processed to RNA seq. Among the top five Differently Expressed Genes (DEGs) that volume plot analysis represented, Ncald and Etnppl showed different tendency between Kdm3b Het mice compared to the wild-type mice. Moreover, approximately 16000 genes of DEGs, 81 genes passed the standard of significant DEGs. Heatmap and Dendrogram analysis showed that each two members of wild-type groups and two members of Kdm3b Het are clustered together. Moreover, some gene levels had been increased in wild-type mice but decreased in Kdm3b Het mice. GO analysis displays that Cellular Component GO terms has brain-related terms which would explain the cerebellum-dependent motor learning deficits. Among three genes, Ntf3 mRNA level is significantly different between two groups. Ncald, Etnppl, and Ntf3 have known to be related with brain function and disorders. This study demonstrates that epigenetic changes, especially the histone methylation, by KDM3B is associated with cerebellum-dependent motor learning deficit. Moreover, this learning deficit is mediated by several neuronal related genes which specific mechanisms would be further studied.