title: Nucleostemin, a coordinator of self-renewal, is expressed in rat marrow stromal cells and turns off after induction of neural differentiation.
abstract: Bone marrow stromal cells (BMSCs) are pluripotent stem cells with self-renewal property and potential to differentiate into a variety of cell types. Identification of the genes responsible for coordination of these processes and elucidation of the mechanisms underlying these events are of fundamental importance. Nucleostemin, a novel p53 binding protein localized in the nucleoli of ESCs, is not expressed in the differentiated cells of adult tissue, suggesting a role in maintaining stem cell self-renewal. In the present study, we have evaluated the expression profile of nucleostemin in rat BMSCs before and after the induction of neural differentiation by RT-PCR and immunocytochemistry. The profile of nucleostemin expression is then compared to the key regulators of proliferation/differentiation such as: Oct-4, Nanog, Neuro D, and Cyclin D1. Our data reveal that there is no detectable expression of Oct-4 and Nanog in either non-differentiated or neurally differentiated BMSCs. In contrast, the expression of nucleostemin is relatively high in non-differentiated BMSCs, then sharply diminishes upon induction of differentiation and finally completely vanishes by 6h after initiation of differentiation. The disappearance of nucleostemin expression coincides with the appearance of Neurofilament-M and -H, MAP2, synaptophysin- and neuron-specific enolase as revealed by RT-PCR and/or immunocytochemistry. Expression of Neuro D and Cyclin D1 also diminish as differentiation proceeds but at much slower rates as compared to nucleostemin. In conclusion, our results suggest that nucleostemin, but not Oct-4 or Nanog, is expressed in BMSCs and it possibly regulates self-renewal proliferation in BMSCs.
authors.affiliation: Department of Genetics, Faculty of Basic Sciences, Tarbiat Modarres University, Tehran, PO Box 14115-175, Iran.
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Yaghoobi
authors.forename: Seyed Javad
authors.initials: SJ
authors.lastname: Mowla
authors.forename: Taki
authors.initials: T
authors.lastname: Tiraihi
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D002352:Carrier Proteins; D002454:Cell Differentiation / Q000502:physiology*; D048430:Cell Shape; D004268:DNA-Binding Proteins / Q000378:metabolism; D019204:GTP-Binding Proteins; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D051381:Rats; D017154:Stromal Cells / Q000166:cytology / Q000502:physiology*
chemical_list: D015415:Biomarkers; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C470310:Gnl3 protein, rat; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3; D019204:GTP-Binding Proteins