Hox Genes: Choreographers in Neural Development, Architects of Circuit Organization

Abstract

Summary The neural circuits governing vital behaviors, such as respiration and locomotion, are comprised of discrete neuronal populations residing within the brainstem and spinal cord. Work over the past decade has provided a fairly comprehensive understanding of the developmental pathways that determine the identity of major neuronal classes within the neural tube. However, the steps through which neurons acquire the subtype diversities necessary for their incorporation into a particular circuit are still poorly defined. Studies on the specification of motor neurons indicate that the large family of Hox transcription factors has a key role in generating the subtypes required for selective muscle innervation. There is also emerging evidence that Hox genes function in multiple neuronal classes to shape synaptic specificity during development, suggesting a broader role in circuit assembly. This review highlights the functions and mechanisms of Hox gene networks, and their multifaceted roles during neuronal specification and connectivity.

DNA methylation analysis of Homeobox genes implicatesHOXB7hypomethylation as risk factor for neural tube defects

“…21 Their cooperative functioning is necessary for the generation of the cranial neural crest and craniofacial diversity. [22][23][24] The spinal cord is a caudal structure, but the neural cells from which it derives initially express rostral, forebrain-like characteristics. The caudal character emerges soon after neural induction, through different extrinsic signals.…”

How to make spinal motor neurons

“…Anatomically, MNs are divided into five major MN columnar identities: the phrenic motor column (PMC), lateral motor column (LMC), preganglionic column (PGC), hypaxial motor column (HMC) and median motor column (MMC) (Dasen and Jessell, 2009;Kanning et al, 2010;Philippidou and Dasen, 2013). MNs of each column reside in stereotypical regions along both the rostro-caudal and dorso-ventral axes.…”

Newt cells secrete extracellular vesicles with therapeutic bioactivity in mammalian cardiomyocytes

“…For example, A1-EVs contain mRNAs that directly regulate early embryonic development, such as transcription factors HOXC6, FOXQ1 and SOX1 [68–73]. The transfer of mRNAs encoding these potent factors, via EVs, may induce terminally differentiated myotubes to dedifferentiate and re-enter the cell cycle [8,9].…”