Hundreds of circular RNAs (circRNAs) are highly abundant in the mammalian brain, often with conserved expression. Here we show that the circRNA Cdr1as is massively bound by the microRNAs (miRNAs) miR-7 and miR-671 in human and mouse brains. When the locus was removed from the mouse genome, knockout animals displayed impaired sensorimotor gating-a deficit in the ability to filter out unnecessary information-which is associated with neuropsychiatric disorders. Electrophysiological recordings revealed dysfunctional synaptic transmission. Expression of miR-7 and miR-671 was specifically and posttranscriptionally misregulated in all brain regions analyzed. Expression of immediate early genes such as, a direct miR-7 target, was enhanced in -deficient brains, providing a possible molecular link to the behavioral phenotype. Our data indicate an in vivo loss-of-function circRNA phenotype and suggest that interactions between Cdr1as and miRNAs are important for normal brain function.

Neurons of the dorsal hindbrain and spinal cord are central in receiving, processing and relaying sensory perception and participate in the coordination of sensory-motor output. Numerous cellular and molecular mechanisms that underlie neuronal development in both regions of the nervous system are shared. We discuss here the mechanisms that generate neuronal diversity in the dorsal spinal cord and hindbrain, and emphasize similarities in patterning and neuronal specification. Insight into the developmental mechanisms has provided tools that can help to assign functions to small subpopulations of neurons. Hence, novel information on how mechanosensory or pain sensation is encoded under normal and neuropathic conditions has already emerged. Such studies show that the complex neuronal circuits that control perception of somatosensory and viscerosensory stimuli are becoming amenable to investigations.

Many disease-causing missense mutations affect intrinsically disordered regions (IDRs) of proteins, but the molecular mechanism of their pathogenicity is enigmatic. Here, we employ a peptide-based proteomic screen to investigate the impact of mutations in IDRs on protein-protein interactions. We find that mutations in disordered cytosolic regions of three transmembrane proteins (GLUT1, ITPR1, and CACNA1H) lead to an increased clathrin binding. All three mutations create dileucine motifs known to mediate clathrin-dependent trafficking. Follow-up experiments on GLUT1 (SLC2A1), the glucose transporter causative of GLUT1 deficiency syndrome, revealed that the mutated protein mislocalizes to intracellular compartments. Mutant GLUT1 interacts with adaptor proteins (APs) in vitro, and knocking down AP-2 reverts the cellular mislocalization and restores glucose transport. A systematic analysis of other known disease-causing variants revealed a significant and specific overrepresentation of gained dileucine motifs in structurally disordered cytosolic domains of transmembrane proteins. Thus, several mutations in disordered regions appear to cause "dileucineopathies."

The GABA (γ-aminobutyric acid)-containing interneurons of the neocortex are largely derived from the ganglionic eminences in the subpallium. Numerous studies have previously defined the migratory paths travelled by these neurons from their origins to their destinations in the cortex. We review here results of studies that have identified many of the genes expressed in the subpallium that are involved in the specification of the subtypes of cortical interneurons, and the numerous transcription factors, motogenic factors and guidance molecules that are involved in their migration.

Vocalization in young mice is an innate response to isolation or mechanical stimulation. Neuronal circuits that control vocalization and breathing overlap and rely on motor neurons that innervate laryngeal and expiratory muscles, but the brain center that coordinates these motor neurons has not been identified. Here, we show that the hindbrain nucleus tractus solitarius (NTS) is essential for vocalization in mice. By generating genetically modified newborn mice that specifically lack excitatory NTS neurons, we show that they are both mute and unable to produce the expiratory drive required for vocalization. Furthermore, the muteness of these newborns results in maternal neglect. We also show that neurons of the NTS directly connect to and entrain the activity of spinal (L1) and nucleus ambiguus motor pools located at positions where expiratory and laryngeal motor neurons reside. These motor neurons control expiratory pressure and laryngeal tension, respectively, thereby establishing the essential biomechanical parameters used for vocalization. In summary, our work demonstrates that the NTS is an obligatory component of the neuronal circuitry that transforms breaths into calls.V ocalization is the primary mechanism used by many vertebrate species for communication (1). Whereas adult mice call during courtship, mating, and territorial disputes, newborn mice use vocalization to communicate with their mothers (2, 3). Newborn mice, when isolated, produce ultrasonic calls (USCs) that elicit search and retrieval behavior by their mothers. Thus, vocalizations of newborn mice represent an innate behavior that is thought to rely on a genetically determined circuit. Such innate vocalizations are reminiscent of nonverbal utterances of humans like laughing, crying, sighing, and moaning.The central circuits that control vocalization have been widely studied in adult vertebrates, where they overlap in their executive components with respiratory circuits (4). Forebrain pathways that control the frequency and sequence of ultrasounds in mice are not essential for innate vocalization (5, 6); rather, it is the periaqueductal gray in the midbrain that modulates the activity of motor neurons in the hindbrain and spinal cord to implement calls and modulate breathing (7,8). Calls are shaped through a biomechanical process that involves variations in subglottal air pressure and laryngeal muscle tension (9, 10). Expiration is an important determinant of subglottal air pressure (11), suggesting that expiratory muscle activity and laryngeal tension are highly coordinated during vocalization. However, because expiratory and laryngeal motor neurons are located at markedly different axial levels of the nervous system, in the spinal cord (T11-L1 levels, expiratory) and hindbrain (nucleus ambiguus, laryngeal), how the activities of these motor pools are coordinated is unclear (12, 13). More importantly, the identity and location of functionally important premotor neurons for vocalization are little known.Using mouse genetics to investigate the ...