CBP/p300 homologs CBP2 and CBP3 play distinct roles in planarian stem cell function

Chromatin modifications function as critical regulators of gene expression and cellular identity, especially in the regulation maintenance pluripotent state. However, many studies chromatin modification stem cells—and cells particular—are performed mammalian cell culture, an vitro condition mimicking a very transient state during development. Thus, new models for studying vivo could be helpful understanding roles modification, confirming prior studies, exploring evolution The freshwater flatworm, Schmidtea mediterranea, is excellent model adult cells, particularly context robust, whole-body regeneration. To identify modifying remodeling enzymes planarian regeneration maintenance, we took candidate approach screened homologs 25 genes known to regulate biology other organisms. Through our study, identified six with novel functions homeostasis, regeneration, behavior. Of list characterized, five CREB-Binding Protein (CBP) p300 family histone acetyltransferases, representing expansion this planarians. We find that two CBP members are required survival, knockdown Smed-CBP2 Smed-CBP3 causing distinct defects or function. Loss CBP2 causes quick, dramatic loss while CBP3 affects more narrowly, influencing differentiation several types include neuronal subtypes eye. Further, Smed-CBP1 fissioning propose division labor among diversified planarians presents opportunity dissect specific broadly important acetyltransferase family.