cell X1 cell PMID:20215344 PMID:22543868 PMID:29906446 PMID:27502555 PMID:18456843 PMID:24992682 PMID:27068018 PMID:29100657 https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4407 X1 population X1 PMID:22385657 X1 neoblast PMID:26711341 PMID:27551436 PMID:20223763 Planarian_Anatomy PMID:23629965 PMID:26114597 PMID:29557542 PMID:24367277 PMID:25254346 PMID:23235145 PMID:19048075 PMID:22427692 PMID:22549959 PMID:28137894 PMID:27150006 PMID:25558068 PMID:24120894 PMID:27013241 PMID:26457503 PMID:17670787 PMID:21937596 PMID:25956527 PMID:18786419 X1 cell population PMID:29674432 PMID:30194301 A sorted cell population enriched for irradiation-sensitive, cycling cells (4n cells, with high levels of Hoescht 33342 staining) with scant cytoplasm (low levels of calcein-AM staining). X1 cells are enriched for cycling neoblasts. PMID:16872450 PMID:27523733 FACS sorted cell population