Identification of a retinoic acid‐responsive neural enhancer in the Ciona intestinalis Hox1 gene. (10th January 2013)

• Record Type: Journal Article
• Authors: Kanda, Miyuki; Ikeda, Taku; Fujiwara, Shigeki
• Is Part Of: Development growth and differentiation. Volume 55:Number 2(2013)
• Page Start: 260
• Page End: 269
• Publication Date: 2013-01-10
• Subjects: Embryology -- Periodicals; Developmental biology -- Periodicals; Growth -- Periodicals; 574.3
• DOI: 10.1111/dgd.12033
• Languages: English
• ISSNs: 0012-1592

Abstract

<abstract abstract-type="main" id="dgd12033-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The <italic>Hox1</italic> gene in the urochordate ascidian <italic>Ciona intestinalis</italic> (<italic>Ci‐Hox1</italic>) is expressed in the nerve cord and epidermis. We identified a nerve cord enhancer in the second intron of <italic>Ci‐Hox1</italic>, and demonstrated that retinoic acid (RA) plays a major role in activating this enhancer. The enhancer contained a putative retinoic acid‐response element (RARE). Mutation of the RARE in the <italic>Ci‐Hox1</italic> nerve cord enhancer only partially abolished the enhancer activity. Genes encoding RA synthase and the RA receptor were knocked down using specific antisense morpholino oligos (MOs), and injection of embryos with these MOs resulted in the complete disappearance of epidermal expression of <italic>Ci‐Hox1</italic> and reduction of neural expression. However, nerve cord expression was not completely repressed. These results suggest that the nerve cord enhancer is activated by two partially redundant pathways; one RA‐dependent and one RA‐independent.</p> </abstract>