title: SmedOB1 is Required for Planarian Homeostasis and Regeneration.
abstract: The planarian flatworm is an emerging model that is useful for studying homeostasis and regeneration due to its unique adult stem cells (ASCs). Previously, planaria were found to share mammalian TTAGGG chromosome ends and telomerases; however, their telomere protection proteins have not yet been identified. In Schmidtea mediterranea, we identified a homologue of the human protection of telomeres 1 (POT1) with an OB-fold (SmedOB1). SmedOB1 is evolutionarily conserved among species and is ubiquitously expressed throughout the whole body. Feeding with SmedOB1 double-stranded RNAs (dsRNAs) led to homeostasis abnormalities in the head and pharynx. Furthermore, several ASC progeny markers were downregulated, and regeneration was impaired. Here we found that SmedOB1 is required for telomeric DNA-protein complex formation and it associates with the telomere TTAGGG sequence in vitro. Moreover, DNA damage and apoptosis signals in planarian were significantly affected by SmedOB1 RNAi. We also confirmed these phenotypes in Dugesia japonica, another flatworm species. Our work identified a novel telomere-associated protein SmedOB1 in planarian, which is required for planarian homeostasis and regeneration. The phylogenetic and functional conservations of SmedOB1 provide one mechanism by which planarians maintain telomere and genome stability to ensure their immortality and shed light on the regeneration medicine of humans.
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Yin
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Zhangfang
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Pengqing
authors.initials: P
authors.lastname: Li
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Junjiu
authors.initials: J
authors.lastname: Huang
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.|Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, USA.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Songyang