PRMT1 is required for the development and/or proliferation of adult intestinal progenitor/stem cells. A. In vivo knock-down of PRMT1 expression. Xenopus laevis tadpoles at stage 53/54 were injected with (MO, Co) or without (Un) PRMT1 (MO) or control (Co) anti-sense Vivo-morpholino oligos for 4 consecutive days. Intestines were dissected for western blot analysis of the expression of the endogenous PRMT1 or histone H4 (as a control). B. Knocking-down the expression of endogenous PRMT1 results in the reduction in the number of proliferating adult cells in the intestine. Stage 53/54 premetamorphic tadpoles were injected without (untreated) or with PRMT1 (MO) or control Vivo-morpholino oligos for four days. All tadpoles were then treated with 5 nM of thyroid hormone for 4 days. The tadpoles were sacrificed and the intestine was analyzed for the number of proliferating adult cells. See  for details.