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Regulation of CD45 expression in human leukemia cells
R Taetle1, H Ostergaard, M Smedsrud
1Division of Hematology/Oncology, University of California, San Diego.
Leukemia
|April 1, 1991
Summary
CD45 antigen expression and activity increase during myeloid cell maturation, controlled by gene transcription. This protein tyrosine phosphatase shows substrate specificity in vivo.
Area of Science:
- Hematology
- Molecular Biology
- Cell Biology
Background:
- CD45 antigen, a tyrosine phosphatase, is crucial for hemopoietic cell function.
- Its expression and role in myeloid differentiation are not fully understood.
- Mechanisms controlling CD45 gene expression and function require further investigation.
Purpose of the Study:
- To investigate the regulation of CD45 expression during myeloid differentiation.
- To determine the functional impact of CD45 on protein tyrosine kinase activity.
Main Methods:
- Induction of differentiation in HL60 and Namalwa leukemia cell lines.
- Analysis of CD45 antigen expression and PTPase activity.
- Radiolabeling, immunoprecipitation, Northern blotting, and nuclear transcription assays.
- Assessment of CD45 interaction with epidermal growth factor (EGF) receptor.
Main Results:
- HL60 cell differentiation induced increased CD45 expression and PTPase activity.
- DMSO treatment of HL60 cells increased CD45 transcripts via gene transcription.
- CD45 PTPase activity did not affect EGF receptor tyrosine phosphorylation in Namalwa cells.
Conclusions:
- CD45 expression is upregulated during myeloid maturation at the transcriptional level.
- CD45 exhibits substrate specificity, not affecting EGF receptor tyrosine kinase activity in intact cells.