TitleGenome-wide identification of tissue-specific enhancers in the Ciona tadpole.
Publication TypeJournal Article
Year of Publication2002
AuthorsHarafuji, N, Keys, DN, Levine, M
JournalProc Natl Acad Sci U S A
Date Published2002 May 14
KeywordsAnimals, Enhancer Elements, Genetic, Forkhead Transcription Factors, Nuclear Proteins, Transcription Factors, Urochordata

Less than 100 cis-regulatory DNAs have been characterized in the context of transgenic metazoan embryos. Here we investigate the feasibility of conducting a genome-wide search for tissue-specific enhancers in the ascidian Ciona intestinalis. A total of 138 random genomic DNA fragments with an average size of 1.7 kb were separately placed 5' of a lacZ reporter gene. Eleven of the lacZ fusion genes displayed localized patterns of expression in tadpole-stage Ciona embryos. At least five of these transgenes appear to contain bona fide tissue-specific enhancers that direct expression in the cerebral vesicle, neural tube, primordial adhesive organ, notochord, and tail epidermis. One of the enhancers maps near Distalless (Ci-Dll-A) and recapitulates most aspects of the endogenous expression pattern, including localized expression in the anterior-most regions of the neurogenic ectoderm. We discuss the prospects of creating a regulatory atlas of the Ciona genome, whereby every enhancer is identified for every gene.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.