Neurodevelopmental disorder risk gene DYRK1A is required for ciliogenesis and brain size in Xenopus embryos

DYRK1A (dual specificity tyrosine-(Y)-phosphorylation-regulated kinase 1 A) is a high confidence autism risk gene that encodes a conserved kinase. In addition to autism, patients with putative loss of function variants in DYRK1A exhibit microcephaly, intellectual disability, developmental delay, and congenital anomalies of the kidney and urinary tract. DYRK1A is also located within the critical region for Down syndrome; therefore, understanding the role of DYRK1A in brain development is crucial for understanding the pathobiology of multiple developmental disorders. To characterize the function of this gene, we leveraged the diploid frog, Xenopus tropicalis. We discover that Dyrk1a is expressed in ciliated tissues, localizes to ciliary axonemes and basal bodies, and is required for ciliogenesis. We also demonstrate that Dyrk1a localizes to mitotic spindles and that its inhibition leads to decreased forebrain size, abnormal cell cycle progression, and cell death during brain development. These findings provide hypotheses about potential mechanisms of pathobiology and underscore the utility of X. tropicalis as a model system for understanding neurodevelopmental disorders. 3 replicates each of 3 pooled dissected stage 46 X. tropicalis brains, either uninjected or bilaterally injected with CRISPR reagents targeting dyrk1a at the 2 cell stage. Trizol extracted RNA, low yield library preparation, and Illumina sequencing.