Regeneration of gross molecular body regions in planaria: from molecules to organs

For many organisms, the establishment and subsequent maintenance of anterop osterior polarity is governed by gene expression in several molecular regio ns. We have identified two novel regionally expressed molecules, TCEN49 and TNEX59, that may be involved in such processes. The analysis of tcen49 mRN A expression and TCEN49 protein localisation in a variety of physiological conditions, the specific arrest of anterior regeneration by exogenous retin oic acid administration, the functional analysis of tcen49 by RNA interfere nce, and the structural similarities between TCEN49 and TNEX59, all suggest that planarian molecular regions reflect deeper morphological, physiologic al and functional compartmentalisation.