DNA damage response and repair pathway modulation by non-histone protein methylation: implications in neurodegeneration
JOURNAL OF CELL COMMUNICATION AND SIGNALING
Authors: Urulangodi, Madhusoodanan; Mohanty, Abhishek
Abstract
Protein post-translational modifications (PTMs) have emerged to be combinatorial, essential mechanisms used by eukaryotic cells to regulate local chromatin structure, diversify and extend their protein functions and dynamically coordinate complex intracellular signalling processes. Most common types of PTMs include enzymatic addition of small chemical groups resulting in phosphorylation, glycosylation, poly(ADP-ribosyl)ation, nitrosylation, methylation, acetylation or covalent attachment of complete proteins such as ubiquitin and SUMO. Protein arginine methyltransferases (PRMTs) and protein lysine methyltransferases (PKMTs) enzymes catalyse the methylation of arginine and lysine residues in target proteins, respectively. Rapid progress in quantitative proteomic analysis and functional assays have not only documented the methylation of histone proteins post-translationally but also identified their occurrence in non-histone proteins which dynamically regulate a plethora of cellular functions including DNA damage response and repair. Emerging advances have now revealed the role of both histone and non-histone methylations in the regulating the DNA damage response (DDR) proteins, thereby modulating the DNA repair pathways both in proliferating and post-mitotic neuronal cells. Defects in many cellular DNA repair processes have been found primarily manifested in neuronal tissues. Moreover, fine tuning of the dynamicity of methylation of non-histone proteins as well as the perturbations in this dynamic methylation processes have recently been implicated in neuronal genomic stability maintenance. Considering the impact of methylation on chromatin associated pathways, in this review we attempt to link the evidences in non-histone protein methylation and DDR with neurodegenerative research.
Chromosomal microarray and whole-exome sequence analysis in Taiwanese patients with autism spectrum disorder
MOLECULAR GENETICS & GENOMIC MEDICINE
Authors: Chang, Ya-Sian; Lin, Chien-Yu; Huang, Hsi-Yuan; Chang, Jan-Gowth; Kuo, Haung-Tsung
Abstract
Background: Autism spectrum disorder (ASD) is defined as a group of genetically and clinically heterogeneous neurodevelopmental disorders. Interplay between de novo and inherited rare variants has been suspected in the development of ASD. Methods: Here, we applied 750K oligonucleotide microarray analysis and wholeexome sequencing (WES) to five trios from Taiwanese families with ASD. Results: The chromosomal microarray analysis revealed three representative known diagnostic copy number variants that contributed to the clinical presentation: the chromosome locations 2q13, 1q21.1q21.2, and 9q33.1. WES detected 22 rare variants in all trios, including four that were newly discovered, one of which is a de novo variant. Sequencing variants of JMJD1C, TCF12, BIRC6, and NHS have not been previously reported. A novel de novo variant was identified in NHS (p.I7T). Additionally, seven pathogenic variants, including SMPD1, FUT2, BCHE, MYBPC3, DUOX2, EYS, and FLG, were detected in four probands. One of the involved genes, SMPD1, had previously been reported to be mutated in patients with Parkinson's disease. Conclusions: These findings suggest that de novo or inherited rare variants and copy number variants may be double or multiple hits of the probands that lead to ASD. WES could be useful in identifying possible causative ASD variants.