Mechanism of Differentiation of HEL Cells
Induced by Hydroxyurea
GUI Chang-Yun,JIANG Chu and QIAN Ruo-Lan
( Shanghai Institute of Cell Biology,the Chinese Academy of
Sciences,Shanghai 200031,China )
Abstract HEL cells,a human erythroleukemia
cell line,mainly express fetal globin gene(γ) and small amount of the
embryonic(ε) globin gene,but not the adult (β) globin gene. Our previous
studies demonstrated that hydroxyurea could induce HEL cells to express adult
(β) globin gene and induce HEL cells to terminal differentiation. In order to
reveal the differentiation mechanism of HEL cells induced by hydroxyurea,GMSA
was performed to examine the binding of nuclear extracts from hydroxyurea
induced and uninduced HEL cells to the positive control region in the 5＇-flanking sequence of human
β-globin gene and to the synthesized GATA oligonucleotides. Our results showed
that,in the nuclear proteins from the induced HEL cells,the binding of GATA-1
to GATA motif was increased. However,the binding of GATA-2 to GATA motif was
decreased. Besides,our data showed that a YY1-like protein was decreased
quickly in hydroxyurea induced HEL cells. Western blotting analysis was used to
analyze variation of GATA proteins in nuclei of HEL cells. Results revealed
that the amount of GATA-2 was significantly decreased while the amount of
GATA-1 was increased after HEL cells were induced for 12 h. These results
indicate that GATA-1 may play a critical role in inducing HEL cells to terminal
differentiation. The YY1-like protein and GATA-2 might inhibit HEL cells from
terminal differentiation.
Key Words Human erythroleukemia cell line；hydroxyurea；globin genes；transcription factors
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