Expression of DjXnp, a novel member of the SNF2-like ATP-dependent chromatin remodelling genes, in intact and regenerating planarians.

SWI/SNF-related complexes include proteins implicated in the regulation of gene expression by chromatin remodelling. We have identified in planarians, invertebrates well-known for their regenerative capability,the cDNA of a novel gene, DjXnp, which encodes a protein of 1,076 amino acids, containing seven helicase domains similar to those found in the SNF2-like family members. Sequence comparison reveals a significant degree of similarity of DjXNP with mammalian XNP/ATRX proteins. In situ hybridization experiments performed on intact and regenerating planarians demonstrated that DjXnp transcripts were distributed in mesenchymal cells and were especially abundant in nerve cells. During anterior regeneration, DjXnp was detected in the blastemal area where the nervous system is newly forming. This expression pattern reveals extensive similarities with that described for mammalian XNP/ATRX, suggesting that these genes may have a conserved function at the cellular level.