Spatial organization of the chicken beta-globin gene domain in erythroid cells of embryonic and adult lineagesReport as inadecuate

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Epigenetics and Chromatin

, 5:16

First Online: 07 September 2012Received: 02 May 2012Accepted: 16 August 2012


BackgroundThe β-globin gene domains of vertebrate animals constitute popular models for studying the regulation of eukaryotic gene transcription. It has previously been shown that in the mouse the developmental switching of globin gene expression correlates with the reconfiguration of an active chromatin hub ACH, a complex of promoters of transcribed genes with distant regulatory elements. Although it is likely that observations made in the mouse β-globin gene domain are also relevant for this locus in other species, the validity of this supposition still lacks direct experimental evidence. Here, we have studied the spatial organization of the chicken β-globin gene domain. This domain is of particular interest because it represents the perfect example of the so-called ‘strong’ tissue-specific gene domain flanked by insulators, which delimit the area of preferential sensitivity to DNase I in erythroid cells.

ResultsUsing chromosome conformation capture 3C, we have compared the spatial configuration of the β-globin gene domain in chicken red blood cells RBCs expressing embryonic 3-day-old RBCs and adult 9-day-old RBCs β-globin genes. In contrast to observations made in the mouse model, we found that in the chicken, the early embryonic β-globin gene, Ε, did not interact with the locus control region in RBCs of embryonic lineage 3-day RBCs, where this gene is actively transcribed. In contrast to the mouse model, a strong interaction of the promoter of another embryonic β-globin gene, ρ, with the promoter of the adult β-globin gene, β, was observed in RBCs from both 3-day and 9-day chicken embryos. Finally, we have demonstrated that insulators flanking the chicken β-globin gene domain from the upstream and from the downstream interact with each other, which places the area characterized by lineage-specific sensitivity to DNase I in a separate chromatin loop.

ConclusionsTaken together, our results strongly support the ACH model but show that within a domain of tissue-specific genes, the active status of a promoter does not necessarily correlate with the recruitment of this promoter to the ACH.

Keywordsβ-globin genes Active chromatin hub Insulator Chicken RBCs AbbreviationsACHActive chromatin hub

bpbase pair

CEFChicken embryonic fibroblast

CTCFCCCTC-binding factor

HSSite of hypersensitivity to DNase I

LCRLocus control region

RBCRed blood cell

RT-qPCRreal-time reverse transcriptase polymerase chain reaction

3C-qPCRquantitative chromosome conformation capture assay.

Electronic supplementary materialThe online version of this article doi:10.1186-1756-8935-5-16 contains supplementary material, which is available to authorized users.

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Author: Sergey V Ulianov - Alexey A Gavrilov - Sergey V Razin


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