The role of zinc finger protein 521/early hematopoietic zinc finger protein in erythroid cell differentiation.
ZNF521 (zinc finger protein 521) is a transcription factor with an N-terminal transcriptional repressor motif and 30 zinc finger domains. Although a high expression level of ZNF521 in human CD34+ progenitors and hematopoietic malignancies has been demonstrated, the functional role of ZNF521 in hematopoietic cell differentiation has not been clarified. In this study, we analyzed the role of ZNF521 in erythroid cell differentiation using the short hairpin RNA (shRNA)-mediated gene silencing method. Down-regulation of ZNF521 mediated by transient expression of shRNA for ZNF521 resulted in increased synthesis of hemoglobin in K562 and HEL cell lines as compared with control cells. K562-derived clones in which ZNF521 was constitutively silenced by shRNA also showed marked synthesis of hemoglobin and an increased expression level of glycophorin A. Since GATA-1 is the key regulator of erythroid differentiation, the effect of ZNF521 on transcription activity of GATA-1 was analyzed using a luciferase assay. GATA-1 activity was markedly inhibited by ZNF521 in a dose-dependent manner. Deletion analysis of ZNF521 showed that the repressive effect requires an N-terminal repression motif. Furthermore, the direct interaction of ZNF521 with GATA-1 was demonstrated. These results indicate that ZNF521 modulates erythroid cell differentiation through direct binding with GATA-1.
Matsubara
Etsuko
E
Department of Bioregulatory Medicine, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan.
Sakai
Ikuya
I
Yamanouchi
Jun
J
Fujiwara
Hiroshi
H
Yakushijin
Yoshihiro
Y
Hato
Takaaki
T
Shigemoto
Kazuhiro
K
Yasukawa
Masaki
M
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism*; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D006021:Glycophorins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D020014:K562 Cells; D051379:Mice; D041681:NIH 3T3 Cells; D011485:Protein Binding / Q000502:physiology; D017384:Sequence Deletion
D004268:DNA-Binding Proteins; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C494689:Gata1 protein, mouse; D006021:Glycophorins; C529598:zinc finger protein 521, human