Characterizing the genotype/phenotype relationship in OCNDS-causing CSNK2A1 variants in vitro
Okur-chung neurodevelopmental syndrome (OCNDS) is a rare disease affecting approximately 220 people. It is characterized by symptoms including intellectual disability and behavioral problems. OCNDS is caused by a mutation in the CSNK2A1 gene, however little is known about the underlying molecular biology. To investigate this we used a neuronal differentiation model to study a possible phenotypic difference between wild type and CSNK2A1 mutant cells. Neuronal progenitor cells (NPCs) were differentiated from induced pluripotent stem cells (iPSCs) and grown for a minimum of six days until confluent for passaging. During NPC maturation, RNA is collected for future bulk sequencing analysis. Immunofluorescence antibody staining was done on day 3 of NPC development. Staining showed a presence of SOX2 in NPCs which is important in the development of NPCs. To optimize our immunofluorescence staining, Wild type and CSNK2A1 variant day 75 neural organoids were used to stain for different proteins; SOX2, Beta-tubulin III (a marker of mature neurons), CK2 Beta (coded by the CSNK2B gene), CSNK2A2 protein (coded by the CSNK2A2 gene). Both the CK2 Beta and the CSNK2A2 proteins are important in different cell processes similar to the CSNK2A1 proteins. Immunofluorescence correctly identified all proteins we stained for showing there is a presence of CK2 Beta, CSNK2A2, Beta-Tubulin and SOX2 within these organoids. SOX2 appears to be increased in the CSNK2A1 variant. Future assays will include immunofluorescence, bulk RNA, mitochondrial analysis, and western blotting. Understanding the molecular biology of the CSNK2A1 OCNDS-causing mutations is crucial for future therapeutic developments.
