Elucidating the roles of BARHL1 in pharynx regeneration

Regeneration is a complex process that requires the generation of new tissue and re-patterning of new and existing organs. Planarians are flatworms that are capable of regenerating any missing body part, including their large muscular pharynx, which they use for feeding and defecating. The planarian pharynx is used as model for studying tissue growth and patterning, because of its ability the regrow following injury, despite the lack of dividing cells inside the pharynx. Here, we study Smed-barlh1, a highly conserved homeobox-encoding gene. We recently found that Smed-barlh1 gene expression is required for maintenance and regeneration of the planarian pharynx, and that inhibition of barlh1 gene expression by RNAi results in the ablation of the pharynx, and appearance of lesions in the pharyngeal cavity. We are characterizing the function of BARLH1 using a combination of in vivo gene function analysis and by establishing marker genes for pinpointing the cells that respond to BARLH1 expression during planarian pharynx maintenance and regeneration. Our study will shed light on a complex developmental and molecular process, and the functions of a highly conserved transcription factor.