The upstream area of the chicken α-globin gene domain is transcribed in both directions in the same cells

AbstractIt was demonstrated previously that in erythroid chicken cells an extended upstream area of the α-globin gene domain is transcribed in both directions as a part of ggPRX gene and a part of a full domain transcript of the α-globin gene domain. Here, we show that both DNA chains of the above-mentioned region are transcribed in the same cells and that the corresponding transcripts coexist in nuclei. The data obtained suggest that cells possess a molecular mechanism which in some cases prevents the formation of dsRNA and subsequent destruction of both transcripts in spite of the presence of complementary RNA chains in the cell nucleus

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

For more than 30 years it was believed that globin gene domains included only genes encoding globin chains. Here we show that in chickens, the domain of α-globin genes also harbor the non-globin gene TMEM8. It was relocated to the vicinity of the α-globin cluster due to inversion of an ∼170-kb genomic fragment. Although in humans TMEM8 is preferentially expressed in resting T-lymphocytes, in chickens it acquired an erythroid-specific expression profile and is upregulated upon terminal differentiation of erythroblasts. This correlates with the presence of erythroid-specific regulatory elements in the body of chicken TMEM8, which interact with regulatory elements of the α-globin genes. Surprisingly, TMEM8 is not simply recruited to the α-globin gene domain active chromatin hub. An alternative chromatin hub is assembled, which includes some of the regulatory elements essential for the activation of globin gene expression. These regulatory elements should thus shuttle between two different chromatin hubs