Biology subjects

Szeto, J.-Y. A.

Publications and source records attributed to Szeto, J.-Y. A..

2 recordsLinked to original sources

bioRxiv2022

Human cellular model systems of β-thalassemia enablein-depth analysis of disease phenotype

{beta}-thalassemia is a prevalent genetic disorder causing severe anemia due to defective erythropoiesis, with few treatment options. Studying the underlying molecular defects is impeded by paucity of suitable patient material. In this study we created human disease cellular model systems for {beta}-thalassemia, which accurately recapitulate the phenotype of patient erythroid cells. We also developed a high throughput compatible fluorometric-based assay for evaluating severity of disease phenotype and utilised the assay to demonstrate positive response of lines to verified reagents, providing validation for such applications. TMT-based comparative proteomics confirmed the same profile of proteins previously reported, whilst providing new insights into the altered molecular mechanisms in {beta}-thalassemia erythroid cells, with upregulation of a wide range of biological pathways and processes observed. Overall, the lines provide a sustainable supply of disease cells as novel research tools, for identifying new therapeutic targets, and as screening platforms for novel drugs and therapeutic reagents.

cell biology↗

bioRxiv2022

Molecular basis of neurodevelopmental disorder-causing mutation in nonsense-mediated mRNA decay factor UPF3B

UPF3B is a key nonsense-mediated mRNA decay (NMD) factor required for surveillance of mRNA and regulation of eukaryotic gene expression. Mutations in UPF3B cause intellectual disability. The underlying molecular mechanisms remain unexplored as the mutations lie in an uncharacterized region of UPF3B. Here, we show that UPF3B shares structural and functional homology to the Drosophila Behavior/Human Splicing protein family comprising an RNA-recognition motif-like domain (RRM-L), a NONA/paraspeckle-like domain (NOPS-L), and extended -helical domains essential for ribosome- and RNA-binding and RNA-induced oligomerization. A co-crystal structure of UPF3B with the third middle domain of eukaryotic initiation factor 4G (MIF4GIII) of UPF2 reveals an unexpectedly intimate binding interface. UPF3Bs disease-causing mutation Y160D located in the NOPS-L domain reduces the UPF2 binding affinity ~40-fold compared to wildtype UPF3B. UPF3Bs paralogue UPF3A, an NMD antagonist which is upregulated in patients with the UPF3B-Y160D mutation, binds UPF2 with ~10-fold higher affinity than UPF3B, leading to impaired NMD activity and upregulation of mRNAs involved in neurodevelopment.

biochemistry↗