Conserved spatiotemporal expression patterns of PRMT1 in the postembryonic intestines of fish and mouse suggest a conserved role of PRMT1 in adult intestinal stem cell development. PRMT1 mRNA was analyzed by in situ hybridization in the intestines of zebrafish at 15 days post fertilization (dpf) (A), 20 dpf (B) and 1 year post fertilization (ypf) (C) and mouse at postnatal day 7 (D, P7), P21 (E), and postnatal week 14 (F, P14w). Arrows indicate PRMT1 positive cells in the intestinal epithelium. Note that high levels of PRMT1 expression is detected only in the proliferating/stem cells located in the crypts in both species, resembling that in Xenopus laevis. In addition, the transition period in both species when PRMT1 is upregulated is characterized by high levels of T3 in the serum, just like that during Xenopus metamorphosis. ep, epithelium. l, lumen. Bars, 50 μm. See  for details.