The UPD3 cytokine couples environmental challenge and intestinal stem cell division through modulation of JAK/STAT signaling in the stem cell microenvironment

► upd3 is required for stimulation of ISC division in response to challenge. ► upd3 is expressed in differentiated ECs and in differentiating EBs. ► upd3 is required for activation of JAK/STAT signaling in EBs and in visceral muscles. ► JAK/STAT signaling is required in EBs and in visceral muscles for ISC division.