TMEM8 - a non-globin gene entrapped in the globin web

Area of Science:

• Genomics
• Molecular Biology
• Gene Regulation

Background:

• Globin gene domains were traditionally thought to exclusively contain globin-encoding genes.
• The TMEM8 gene's function and genomic location were previously uncharacterized in avian erythropoiesis.

Purpose of the Study:

• To investigate the genomic organization of the alpha-globin gene domain in chickens.
• To determine the expression pattern and regulatory mechanisms of the TMEM8 gene in chicken erythroid cells.

Main Methods:

• Comparative genomics to identify gene rearrangements.
• Gene expression analysis (e.g., RT-qPCR) in different cell types and differentiation stages.
• Chromatin conformation capture (3C) techniques to study long-range DNA interactions.

Main Results:

• The TMEM8 gene is located within the chicken alpha-globin gene domain, repositioned by a 170-kb genomic inversion.
• Chicken TMEM8 exhibits erythroid-specific expression, contrasting with its human T-lymphocyte expression.
• Erythroid-specific regulatory elements within TMEM8 interact with alpha-globin regulatory elements.
• TMEM8 forms a novel chromatin hub involving globin gene regulatory elements.

Conclusions:

• The alpha-globin gene domain is more complex than previously assumed, harboring non-globin genes like TMEM8.
• TMEM8 plays a critical role in erythroid differentiation in chickens, regulated by erythroid-specific elements.
• Gene regulatory elements can shuttle between distinct chromatin hubs to coordinate gene expression during cellular differentiation.