title: The vertebrate Hox gene regulatory network for hindbrain segmentation: Evolution and diversification: Coupling of a Hox gene regulatory network to hindbrain segmentation is an ancient trait originating at the base of vertebrates.
abstract: Hindbrain development is orchestrated by a vertebrate gene regulatory network that generates segmental patterning along the anterior-posterior axis via Hox genes. Here, we review analyses of vertebrate and invertebrate chordate models that inform upon the evolutionary origin and diversification of this network. Evidence from the sea lamprey reveals that the hindbrain regulatory network generates rhombomeric compartments with segmental Hox expression and an underlying Hox code. We infer that this basal feature was present in ancestral vertebrates and, as an evolutionarily constrained developmental state, is fundamentally important for patterning of the vertebrate hindbrain across diverse lineages. Despite the common ground plan, vertebrates exhibit neuroanatomical diversity in lineage-specific patterns, with different vertebrates revealing variations of Hox expression in the hindbrain that could underlie this diversification. Invertebrate chordates lack hindbrain segmentation but exhibit some conserved aspects of this network, with retinoic acid signaling playing a role in establishing nested domains of Hox expression.
authors.affiliation: Stowers Institute for Medical Research, Kansas City, MO, USA.
authors.forename: Hugo J
authors.initials: HJ
authors.lastname: Parker
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
authors.forename: Marianne E
authors.initials: ME
authors.lastname: Bronner
authors.affiliation: Stowers Institute for Medical Research, Kansas City, MO, USA.|Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS, USA.
authors.forename: Robb
authors.initials: R
authors.lastname: Krumlauf
mesh_terms: D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning; D043344:Chordata / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D005801:Genes, Homeobox / Q000235:genetics*; D006801:Humans; D012249:Rhombencephalon / Q000196:embryology / Q000378:metabolism*
keywords: Hox genes; chordates; gene regulatory networks; hindbrain; rhombomeres; segmentation; vertebrate evolution