RBMX gene is essential for brain development in zebrafish

Authors

  • Enkhjargal Tsend-Ayush,

    Corresponding author
    1. Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
    • Research School of Biological Sciences, Australian National University, Canberra, ACT 2601, GPO Box 475, Australia
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  • Lynda A. O'Sullivan,

    1. Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Melbourne, Australia
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  • Frank S. Grützner,

    1. Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
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  • Sara M.N. Onnebo,

    1. Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Melbourne, Australia
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  • Rowena S. Lewis,

    1. Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Melbourne, Australia
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  • Margaret L. Delbridge,

    1. Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
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  • Jennifer A. Marshall Graves,

    1. Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
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  • Alister C. Ward

    1. Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Melbourne, Australia
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Abstract

The human RBMX gene was discovered recently through its homology to the spermatogenesis candidate gene RBMY. Its position on the human X chromosome suggests that it may be involved in X-linked mental retardation syndromes. However, to date there is scant information on the in vivo role of RBMX. To address this issue, we have isolated a zebrafish rbmx orthologue and characterized its embryonic expression pattern. Zebrafish rbmx is maternally expressed and then widely expressed in the embryo up to 24 hr postfertilization. In later stages of embryonic development, rbmx transcripts are localized predominantly in the brain, branchial arches, and liver primordium. The function of rbmx during embryonic development was examined by the use of an antisense morpholino targeting rbmx. The rbmx-morphants displayed an underdeveloped head and eyes, reduced body size, defective somite patterning, and absence of jaws. Furthermore, in the absence of functional rbmx, expression of specific markers for the fore- and hindbrain (otx2, krox20) was severely reduced. These studies demonstrate for the first time that rbmx is required for normal embryonic development, in particular of the brain, consistent with a role in X-linked mental retardation. Developmental Dynamics 234:682–688, 2005. © 2005 Wiley-Liss, Inc.

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