Homeobox genes in vertebrate forebrain development and disease

Authors

  • JT Wigle,

    1. Department of Biochemistry & Medical Genetics
    2. Institute of Cardiovascular Sciences
    3. St. Boniface General Hospital Research Centre
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  • DD Eisenstat

    Corresponding author
    1. Department of Biochemistry & Medical Genetics
    2. Department of Pediatrics & Child Health
    3. Department of Human Anatomy & Cell Science
    4. Department of Ophthalmology
    5. Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba, Canada
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David D. Eisenstat, MD, MA, FRCPC, Manitoba Institute of Cell Biology, 675 McDermot Avenue, Room 5016, Winnipeg, Manitoba, Canada R3E 0V9.
Tel.: +1 204 787 1169;
fax: +1 204 787 2190;
e-mail: eisensta@cc.umanitoba.ca

Abstract

Homeobox genes are an evolutionarily conserved class of transcription factors that are key regulators of developmental processes such as regional specification, patterning, migration and differentiation. In both mouse and humans, the developing forebrain is marked by distinct boundaries of homeobox gene expression at different developmental time points. These genes regulate the patterning of the forebrain along the dorsal/ventral and rostral/caudal axes and are also essential for the differentiation of specific neuronal subtypes. Inhibitory interneurons that arise from the ganglionic eminences and migrate tangentially to the neocortex and hippocampus are dramatically affected by mutations in several homeobox genes. In this review, we discuss the identification, expression patterns, loss- and/or gain-of-function models, and confirmed transcriptional targets for a set of homeobox genes required for the correct development of the forebrain in the mouse. In humans, mutations of homeobox genes expressed in the forebrain have been shown to result in mental retardation, epilepsy or movement disorders. The number of homeobox genes currently linked to human nervous system disease is surprisingly low, perhaps reflecting the essential functions of these genes throughout embryogenesis or the degree of functional redundancy during central nervous system development.

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