Genotyping of a Dyrk1a conditional mutant mice

Abstract

DYRK1A is a protein kinase involved in multiple cellular functions through its interaction with different substrates, such as transcription factors, splicing machinery components, RNA polymerase II, chromatin regulators, Cyclin D, Caspase-9 or RNF169. This kinase regulates brain growth and several evidences indicate that DYRK1A may control neuron production, physiological apoptosis in differentiating neurons and neuron differentiation. Previous experiments of the group showed that Dyrk1a null mutant mice (Dyrk1a-/-) are embryonic lethal. Dyrk1a-/- embryos showed developmental delay, growth retardation and defects in the maturation of the neural tube. These mutant embryos die at the beginning of neurogenesis, around embryonic day (E) 11.5, thus precluding the use of this model to study the role of DYRK1A in brain development. Mice with only a functional Dyrk1a allele (Dyrk1a+/-) were viable but also showed affectations in the nervous system. They had a small brain and thinner retinas that correlates with an enhanced developmental apoptosis and defects in the division mode of the neural progenitors. Dyrk1a+/- mice are a phenocopy of patients with DYRK1A haploinsufficiency syndrome, which is caused by loss-of-function mutations in the DYRK1A gene. Patients with this syndrome present microcephaly, intellectual disability, growth retardation, speech problems, developmental delay and behavioural problems. Human DYRK1A gene is in chromosome 21 and studies in transgenic mouse models carrying 3 copies of Dyrk1a have shown that the overexpression of DYRK1A causes a reduction in neuronal cell production in the developing cerebral cortex that are similar to those reported in Down syndrome brains. Therefore, Dyrk1a+/- mice and Dyrk1a transgenic mice are good models to study the effect of DYRK1A dosage imbalance in human syndromes. However, little is known about the different functions/activities regulated by DYRK1A during neurogenesis. In this work we present the crossings and genotyping in order to generate a conditional Dyrk1a knockout mouse. In this data we provide how to perform a mutant mouse with Dyrk1a gene truncated in all neural progenitors by following a specific mating strategy understanding how alleles are segregated and a mice selection with a genotyping analysis. This deletion takes place before the onset of neurogenesis, allowing the study of the effect of a Dyrk1a null mutation in neural progenitor cell