Development, Vol 111, Issue 3 821-828, Copyright © 1991 by Company of Biologists

JOURNAL ARTICLES

Molecular cloning and expression of a novel homeobox gene AHox1 of the ascidian, Halocynthia roretzi

H Saiga, A Mizokami, KW Makabe, N Satoh and T Mita
Department of Molecular Biology, University of Occupational and Environmental Health, Kitakyushu, Japan.

We have isolated a novel ascidian homeobox gene, designated AHox1, by screening the genomic DNA of Halocynthia roretzi with the Bombyx mori Antennapedia type homeobox as a probe. The AHox1 gene encodes a protein that consists of 741 amino acids. The homeobox of AHox1 is interrupted by 2 introns each of which is about 300 bp in length and it shows about 70% similarity at a deduced amino acid level to that of Drosophila H2.0. This suggests that AHox1 is one of the most diverged homeobox genes so far characterized. Northern blot hybridization with an AHox1 probe showed the presence of single transcripts approximately 2.8 kb in length in larvae, juveniles and some adult tissues. The expression of AHox1 is scarcely detected during the course of early development but it increases to a moderate level at the larval stage. After metamorphosis, the level of AHox1 expression increases as development proceeds. In situ hybridization to the juvenile 7 days after metamorphosis showed that the site of AHox1 expression is the epithelium of digestive tract. Among the adult tissues examined, digestive tract, digestive gland and coelomic cells were the major sites of the expression of AHox1. In gonad, body wall muscle and pharyngeal epithelium, the expression of AHox1 is relatively weak. These results suggest that AHox1 is primarily expressed in the tissues of endodermal origin and that the gene expression may be associated with differentiation of the endodermal tissues.

This article has been cited by other articles:

				Y Katsuyama, S Wada, S Yasugi, and H Saiga Expression of the labial group Hox gene HrHox-1 and its alteration induced by retinoic acid in development of the ascidian Halocynthia roretzi Development, January 10, 1995; 121(10): 3197 - 3205. [Abstract] [PDF]

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