Identification of an Embryonic Erythroid Nuclear Factor Binding to the Positive Stage-specific Regulatory Element of the Human epsilon-Globin Gene.
The erythroid- and developmental stage-specific expression of the human epsilon-globin gene is controlled, in part, by the 5'-flanking DNA sequences of this gene. In the present study, a nuclear transacting factor of molecular weight about 80 kD epsilon-SSP in K562 cell (a human embryonic erythroid cell line) was identified by gel mobility shift assay, DNaseI footprinting assay and Southwestern blot assay. It could specifically bind to a positive stage-specific regulatory element (-446 bp to -419 bp, termed epsilon-PREII) of the human epsilon-globin gene. Our data suggested that this nuclear factor (termed epsilon-SSP) might be an erythroid- and stage-specific protein. In addition, we observed that the shift band of this protein bound with the epsilon-PREII could be competed by DNA fragments derived from the human epsilon-globin gene promoter(-177 bp to +1 bp), the DNaseI hypersensitive site 2 (-10 965 bp to -10 681 bp) and the hypersensitive site 3(-14 993 bp to -14 718 bp) of beta-LCR, suggesting that epsilon-SSP might be involved in the developmental regulation of human epsilon-globin gene through the interaction between the proximal (promoter) and the distal (LCR) cis-acting elements.
Yan
Zhi-Jiang
ZJ
Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031, China.
Chen
Ya-Di
YD
Qian
Ruo-Lan
RL