YY1 and GATA-1 interaction modulate the chicken 3'-side alpha-globin enhancer activity

Area of Science:

• * Molecular Biology
• * Gene Regulation
• * Developmental Biology

Background:

• * The chicken alpha-globin domain serves as a model for studying gene regulation.
• * Previously identified silencer-enhancer elements are located on the 3'-side of this domain.
• * Characterizing the enhancer's regulatory role and interacting factors is crucial.

Purpose of the Study:

• * To define the expression influence range of the alpha-globin enhancer.
• * To identify ubiquitous and stage-specific transcriptional regulators interacting with the enhancer.
• * To elucidate the functional impact of these interactions and chromatin modifications.

Main Methods:

• * Systematic functional analysis of the enhancer region.
• * Identification of transcription factor binding sites (GATA-1, EKLF, NF-E2, YY1).
• * Investigation of protein-protein interactions (GATA-1 and YY1) and chromatin conformation using histone deacetylation inhibitors.

Main Results:

• * The enhancer includes a core element with three GATA-1 sites and a 120 bp fragment for EKLF, NF-E2, and a fourth GATA-1 factor.
• * Transcriptional factor Ying Yang 1 (YY1) binds to the 120 bp fragment, with its effect being GATA-1-dependent.
• * A novel physical interaction between GATA-1 and YY1 was identified, influencing enhancer function.
• * Enhancer down-regulation in pre-erythroblasts may involve closed chromatin conformation.

Conclusions:

• * The alpha-globin enhancer has a more intricate composition than previously understood.
• * Differential interactions of nuclear factors and chromatin modifications modulate enhancer activity across erythroid stages.
• * This provides new insights into the complex regulation of alpha-globin gene expression.