Tseng, Y.-T.Y.-T.TsengLi, S.-W.S.-W.LiHuangFu, W.-C.W.-C.HuangFuYen, Y.Y.YenI-HSUAN LIU2021-02-052021-02-052020https://www.scopus.com/inward/record.url?eid=2-s2.0-85090941669&partnerID=40&md5=2c799cf7d51caa4d39af6e2c4b3ea895https://scholars.lib.ntu.edu.tw/handle/123456789/548567Background: Mitochondrial DNA maintenance defects (MDMDs) is one of the critical pediatric dysfunction. One of the recent report indicated that a severe patient of MDMDs carries the NP_056528.2:p.Asn221Ser (N221S) variation in the RRM2B gene (NM_015713.5). However, there is no direct evidence demonstrating the nature of the N221S variation. Materials and Methods: This study aimed to utilize zebrafish and morpholino oligomer (MO) knockdown technique to provide direct evidence for the nature of the N221S variation in the RRM2B. Results: The results showed that two distinct MOs were both able to perturb the expression of rrm2b in zebrafish and dose-dependently induced morphological defects. Furthermore, co-injection of human wild-type RRM2B mRNA with MO-e4i4 successfully rescued the developmental defects, whereas co-injection of RRM2B/N221S mRNA with MO-e4i4 did not rescue the developmental defects. Conclusion: In conclusion, the functional assay in this study provided the direct evidence proving that the N221S variation is a loss-of-function mutation and plausibly related to the pathogenic developmental defects found in the infants of previous clinical reports. ? 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC[SDGs]SDG3cell cycle protein; ribonucleotide reductase; RRM2B protein, human; animal; disorders of mitochondrial functions; genetics; human; loss of function mutation; metabolism; muscular dystrophy; point mutation; zebra fish; Animals; Cell Cycle Proteins; Humans; Loss of Function Mutation; Mitochondrial Diseases; Muscular Dystrophies; Point Mutation; Ribonucleotide Reductases; Zebrafishjournal article10.1002/mgg3.1497329311592-s2.0-85090941669WOS:000569172600001