As a result of screen searching for proteins interacting with MEF-2 transcription factor, we have identified the hda-7 gene in Caenorhabditis elegans. The hda-7 locus encodes a class II histone deacetylase containing a highly conserved catalytic domain. C elegans HDA-7 protein translated in vitro demonstrated a direct interaction with CeMEF-2, as shown in other organisms. CeHDA-7 is abundantly expressed in body-wall muscle cells, neurons, and hypodermal seam cells, similar to CeMEF-2 expression patterns. Consistent with previously known phenotypes observed in mef-2 deletion mutants [Dev. Biol. 223 (2000) 431], RNA interference targeted for hda-7 did not result in muscle function or developmental defects. (C) 2002 Elsevier Science (USA). All rights reserved.