アクティブボード・２０１５年１０月
　　　　　・・・・・２０１５年１０月　５日更新・・・・・
研究発表を行った学会；
・第120回日本解剖学会総会・全国学術集会、
　第92回日本生理学会大会合同大会
　２０１５年　３月２１日〜２３日（神戸）
タイトル；Functional characterization of Ftsj1, a X-linked mental retardation related gene.
発表者；永芳　友　氏
　　　（熊本大学　大学院生命科学研究部　分子生理学分野）
要旨；
Genetic mutations in X chromosome-linked genes have been associated with mental retardation (XLMR). Recently, linkage analyses performed in Belgian, Chinese and Japanese families have identified Ftsj1 gene as a novel candidate gene. Ftsj1 shares homology with a bacterial 23S rRNA methyltransferase FTSJ.
However, the molecular function of Ftsj1 and its pathological relevance in mental retardation have remained unknown. Using Ftsj1 knockout mice, we demonstrate that Ftsj1 methylates cytosolic transfer RNAs (tRNAs) at position 32 and 34. While the FTSJ1 KO mouse developed normally, we observed a decreased protein synthesis level in hippocampus of FTSJ1 KO mice using puromycin-mediated in vivo pulse-labeling technique. Especially, there was a marked decreased of synaptic proteins including glutamate receptors and signaling molecules. The decreased protein synthesis level resulted in the electrophysiological and morphological abnormalities in hippocampal neurons of FTSJ1 KO mice.
There results suggest that the accumulation of hypomodified tRNAs disturbs neuronal protein synthesis, which ultimately contributes to the development of mental retardation in Ftsj1-deficient mice and human.