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Downregulation of Wilms' tumor gene (wt1) during myelomonocytic differentiation in HL60 cells
1Department of Internal Medicine (Section 1), Sapporo Medical University School of Medicine, Japan.
Abstract:
The putative Wilms' tumor-suppressor gene (wt1) encodes a zinc finger DNA binding protein that functions as a transcription repressor. The wt1 gene expression corresponds to kidney development, suggesting a role for this gene in nephroblast differentiation. Here we show that wt1 mRNA expression was downregulated during terminal differentiation of promyelocytic HL60 cells. When HL60 cells were induced to differentiate to granulocytes by dimethyl sulfoxide (DMSO) or retinoic acid (RA), a marked downregulation in the levels of wt1 transcripts was found. The wt1 transcripts were also downregulated in HL60 cells during differentiation to monocytes by vitamin D3 or 12-o-tetradecanoyl-phorbol-13-acetate. Nuclear run-on transcription studies showed the transcriptional rate of wt1 gene was not significantly altered during DMSO-induced granulocytic differentiation, suggesting the downregulation was mostly caused by posttranscriptional modification. Importantly, wt1 transcripts were not significantly altered in K562 cells by treatments with DMSO or RA, which do not induce differentiation of K562 cells. These findings suggest that wt1 gene expression may be downregulated as a differentiation-linked event in HL60 cells.
Insights
The Wilms
Area of Science:
- Cell Biology
- Molecular Biology
- Developmental Biology
Background:
- The Wilms' tumor-1 (WT1) gene encodes a transcription factor crucial for kidney development.
- WT1's role in nephroblast differentiation suggests its broader involvement in cell differentiation processes.
- Understanding WT1's function in differentiation is key to comprehending developmental disorders and potential therapeutic targets.
Purpose of the Study:
- To investigate the expression pattern of Wilms' tumor-1 (WT1) mRNA during the terminal differentiation of promyelocytic HL60 cells.
- To determine if WT1 gene expression is linked to the differentiation process in HL60 cells.
- To explore the regulatory mechanisms underlying WT1 downregulation during cell differentiation.
Main Methods:
- Inducing differentiation of HL60 cells into granulocytes using dimethyl sulfoxide (DMSO) or retinoic acid (RA).
- Inducing differentiation of HL60 cells into monocytes using vitamin D3 or 12-o-tetradecanoyl-phorbol-13-acetate (TPA).
- Analyzing WT1 transcript levels using quantitative methods.
- Performing nuclear run-on assays to assess WT1 gene transcriptional activity.
Main Results:
- WT1 mRNA levels were significantly downregulated in HL60 cells upon induction of differentiation into granulocytes (DMSO, RA) or monocytes (vitamin D3, TPA).
- Nuclear run-on assays indicated that the downregulation of WT1 transcripts during DMSO-induced granulocytic differentiation was primarily due to posttranscriptional regulation, not altered transcription.
- WT1 transcripts remained unchanged in K562 cells treated with DMSO or RA, as these agents do not induce differentiation in K562 cells.
Conclusions:
- WT1 gene expression is downregulated during the terminal differentiation of HL60 cells, suggesting a role in this process.
- The downregulation of WT1 appears to be primarily regulated at the posttranscriptional level.
- WT1 downregulation is a differentiation-linked event specific to cell types capable of differentiation.