Screening of Genes Related to the Expression of Human epsilon-globin Gene by Using Yeast One-hybrid System

The developmental stage-specific silencing of the human epsilon-globin gene during embryonic period is controlled, in part, by a silencer (from -392 to -177 bp) upstream of this gene. In our previous work, by using DNase I footprinting assay, a major protected region from -278 to -235 bp within this silencer DNA was identified. In order to isolate genes encoding proteins that bind to this target element, a human fetal liver cDNA library was screened by using yeast one-hybrid system. The candidate clones were sequenced, and the ribosomal protein L3 (RPL3) was preliminarily isolated. Electrophoretic mobility shift assay (EMSA) and competition tests also demonstrated its binding activity to the target element. These imply that RPL3 might play an important role in silencing the human embryonic epsilon-globin gene expression through the interaction with this silencer.