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Multiple enhancers contribute to expression of the NK‐2 homeobox gene ceh‐22 in C. elegans pharyngeal muscle
Author(s) -
Kuchenthal Craig A.,
Chen Wei,
Okkema Peter G.
Publication year - 2001
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/gene.10018
Subject(s) - enhancer , biology , homeobox , gene , reporter gene , pharyngeal muscles , gene expression , enhancer rnas , regulation of gene expression , enhancer trap , genetics , microbiology and biotechnology , pharynx , anatomy
Summary: Gene expression in the pharyngeal muscles of C. elegans is regulated in part by the NK‐2 family homeodomain factor CEH‐22, which is structurally and functionally related to Drosophila Tinman and the vertebrate Nkx2–5 factors. ceh‐22 is expressed exclusively in the pharyngeal muscles and is the earliest gene known to be expressed in this tissue. Here we characterize the ceh‐22 promoter region in transgenic C. elegans . A 1.9‐kb fragment upstream of ceh‐22 is sufficient to regulate reporter gene expression in a pattern identical to the endogenous gene. Within this promoter we identified two transcriptional enhancers and characterized their cell type and temporal specificity. The distal enhancer becomes active in the pharynx near the time that ceh‐22 expression initiates; however, it becomes active more broadly later in development. The proximal enhancer becomes active after the onset of ceh‐22 expression, but it is active specifically in the ceh‐22 ‐expressing pharyngeal muscles. We suggest these enhancers respond to distinct signals that initiate and maintain ceh‐22 gene expression. Proximal enhancer activity requires a short segment containing a CEH‐22 responsive element, suggesting that CEH‐22 autoregulates its own expression. genesis 31:156–166, 2001. © 2001 Wiley‐Liss, Inc.