Project description:Myt1l is a transcription factor for neuronal induction and maintenance during development and Myt1l is highly implicated in autism spectrum disorder (ASD). Myt1l-mutant mice with a heterozygous deletion of exon 9 showed mild autistic-like behaviors (Social deficit and specific repetitive behaviors) and additional behavioral abnormalities including hyperactivity and anxiolytic-like behaviors in adult. To explore the molecular patterns and mechanisms underlying these behavioral abnormalities, we performed RNA-seq analysis of whole brain from wild-type and Myt1l-mutant mice longitudinally from pup stage (~P3) to juvenile (~P21) and adult (~P56) stages. Myt1l-mutant mice showed upregulations of chromosome- and chromatin-related genes and downregulations of synapse- and neurotransmitter-related genes during pup stage. However, from juvenile stage, Myt1l-mutant mice showed upregulations of extracellular matrix- and transporter-related genes and downregulations of mitochondria- and ribosome-related genes. In addition, Myt1l-mutant mice showed pro-ASD transcriptomic patterns on pup stage, but these patterns were reversed toward anti-ASD transcriptomic patterns from juvenile stages to adult stage as compensatory changes likely. These results suggest that the haploinsufficiency of Myt1l acutely alters the transcriptomic pattern into pro-ASD patterns and chronically compensates with the synapse maturation.
Project description:Myt1l, a zinc-finger transcription factor, promotes neuronal differentiation and is implicated in autism spectrum disorders (ASD) and intellectual disability. However, it was previously unclear whether Myt1l promotes neuronal differentiation in vivo, how its deficiency leads to disease-related mouse phenotypes, and whether and how ASD-risk genes with strong embryonic and perinatal gene expression can yield strong adult-stage ASD-related phenotypes. Here, we report that Myt1l-heterozygous knockout (Myt1l-HT) mice display postnatal age-differential ASD-like phenotypes: Newborn Myt1l-HT mice show ASD-like transcriptomic changes involving suppressed neuronal and synaptic gene expression and suppressed right reflex. Juvenile Myt1l-HT mice display mixed ASD-like and reverse-ASD transcriptomic patterns and large normal behaviors, accompanying increased prefrontal excitatory synaptic transmission. However, adult Myt1l-HT mice show additional ASD-like transcriptomic changes involving astrocytic and microglial genes, along with behavioral deficits and excessive prefrontal inhibitory synaptic transmission. Therefore, Myt1l HT leads to newborn-stage ASD-like neuronal suppression, temporary juvenile normalization, and subsequent adult-stage ASD-like deficits.