Positional information specifies the site of organ regeneration and not tissue maintenance in planarians

• DOI: 10.7554/elife.33680
• Publication Date: 2018-03-16T13:03:50Z
• Authors: Eric M Hill; Christian P Petersen
• Keywords: Homeostasis; Planarian; Planaria; Regenerative process

Most animals undergo homeostatic tissue maintenance, yet those capable of robust regeneration in adulthood use mechanisms significantly overlapping with homeostasis. Here we show planarians that modulations to body-wide patterning systems shift the target site for eye while still enabling homeostasis eyes outside this region. The uncoupling and regeneration, which can occur during normal positional rescaling after axis truncation, is not due altered injury signaling or stem cell activity, nor specific tissue. Rather, pre-existing tissues, are misaligned factor expression domains, compete properly located organs incorporation migratory progenitors. These observations suggest factors determine sites organ but do solely location properties provide candidate explanations how integrates tissues regenerative abilities could be lost evolution development without eliminating long-term maintenance repair.