High impact information on ceh-22

• Development of pharyngeal muscle in nematodes and cardiac muscle in vertebrates and insects involves the related homeobox genes ceh-22, nkx2.5, and tinman, respectively [1].
• We propose that it is the combination of pha-4 and regulatory molecules such as ceh-22 that produces the specific gene expression patterns during pharynx development [2].
• We also show that ectopic PHA-4 can activate ectopic expression of the ceh-22 gene, a pharyngeal-specific NK-2-type homeodomain protein previously shown to bind a muscle-specific enhancer near the PHA-4 binding site in the myo-2 promoter [2].
• The Caenorhabditis elegans NK-2 homeobox gene ceh-22 activates pharyngeal muscle gene expression in combination with pha-1 and is required for normal pharyngeal development [3].
• Here we report that POP-1/TCF and SYS-1/beta-catenin directly activate transcription of ceh-22/nkx2.5 isoforms in SGP distal daughters, a finding that confirms the proposed model of Wnt/MAPK signaling [4].

Biological context of ceh-22

• An early pharyngeal muscle enhancer from the Caenorhabditis elegans ceh-22 gene is targeted by the Forkhead factor PHA-4 [5].
• In this paper, we examine the role CEH-22 plays in pharyngeal muscle development and gene activation by (a) ectopically expressing ceh-22 in transgenic C. elegans and (b) examining the phenotype of a ceh-22 loss-of-function mutant [3].
• A 1.9-kb fragment upstream of ceh-22 is sufficient to regulate reporter gene expression in a pattern identical to the endogenous gene [6].
• Here we characterize the ceh-22 promoter region in transgenic C. elegans [6].

Physical interactions of ceh-22

• Multimerized de209 enhances transcription similarly to DE3 specifically in the pharyngeal muscles, suggesting it may be an essential site regulating ceh-22. de209 binds the pan-pharyngeal Forkhead factor PHA-4 in vitro and responds to ectopic pha-4 expression in vivo, suggesting that PHA-4 directly initiates ceh-22 expression through de209 [5].

Other interactions of ceh-22

• We also examine the relationship between ceh-22 and the pharyngeal organ-specific differentiation gene pha-1 [3].
• We also present evidence that pha-2 regulates itself positively in pm5 cells, that it is a downstream target of the forkhead gene pha-4, and that it may also act in the isthmus as an inhibitor of the ceh-22 gene, an Nkx2.5 homolog [7].

References