Genome-wide identification of tissue-specific enhancers in the Ciona tadpole.
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.
Harafuji
Naoe
N
Department of Molecular and Cell Biology, Division of Genetics and Development, University of California, Berkeley, CA 94720, USA.
Keys
David N
DN
Levine
Michael
M
D000818:Animals; D004742:Enhancer Elements, Genetic; D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014561:Urochordata / Q000235:genetics*
D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors