Transcription factor ZNF25 is associated with osteoblast differentiation of human skeletal stem cells.
The differentiation of human bone marrow derived skeletal stem cells (known as human bone marrow stromal or mesenchymal stem cells, hMSCs) into osteoblasts involves the activation of a small number of well-described transcription factors. To identify additional osteoblastic transcription factors, we studied gene expression of hMSCs during ex vivo osteoblast differentiation.



Clustering of gene expression, and literature investigation, revealed three transcription factors of interest - ZNF25, ZNF608 and ZBTB38. siRNA knockdown of ZNF25 resulted in significant suppression of alkaline phosphatase (ALP) activity. This effect was not present for ZNF608 and ZBTB38. To identify possible target genes of ZNF25, we analyzed gene expression following ZNF25 siRNA knockdown. This revealed a 23-fold upregulation of matrix metallopeptidase 1 and an 18-fold upregulation of leucine-rich repeat containing G protein-coupled receptor 5 and RAN-binding protein 3-like. We also observed enrichment in extracellular matrix organization, skeletal system development and regulation of ossification in the entire upregulated set of genes. Consistent with its function as a transcription factor during osteoblast differentiation of hMSC, we showed that the ZNF25 protein exhibits nuclear localization and is expressed in osteoblastic and osteocytic cells in vivo. ZNF25 is conserved in tetrapod vertebrates and contains a KRAB (Krueppel-associated box) transcriptional repressor domain.



This study shows that the uncharacterized transcription factor, ZNF25, is associated with differentiation of hMSC to osteoblasts.
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
Natalie A
NA
Twine
Department of Endocrinology and Metabolism, Endocrine Research Laboratory (KMEB), Odense University Hospital, Odense, Denmark.|Present Address: Pluripotent Stem Cell Group, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia.
Linda
L
Harkness
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.|Department of Endocrinology and Metabolism, Endocrine Research Laboratory (KMEB), Odense University Hospital, Odense, Denmark.|Stem Cell Unit, Department of Anatomy, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.
Moustapha
M
Kassem
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia. m.wilkins@unsw.edu.au.
Marc R
MR
Wilkins
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002113:Calcification, Physiologic; D002454:Cell Differentiation / Q000235:genetics*; D019143:Evolution, Molecular; D015870:Gene Expression; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D005810:Multigene Family; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D010012:Osteogenesis / Q000235:genetics; D019098:Telomerase / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014714:Vertebrates; D016335:Zinc Fingers
D014157:Transcription Factors; D019098:Telomerase; D000469:Alkaline Phosphatase
Human transcription factors; Mesenchymal stem cells; Osteoblasts; Osteogenesis; ZNF25