Skip to main content


Fig. 2 | BMC Medical Genomics

Fig. 2

From: Genomic approaches to identifying targets for treating β hemoglobinopathies

Fig. 2

HbF Gene Expression is controlled by Cis- and Trans-acting elements. Shown, not to scale is the LCR, the γ-globin genes and the β-globin gene. γ-Globin and α globin (not shown) form HbF while β-globin and α globin form adult HbA. The major known transcription factors that have been implicated in hemoglobin switching are shown along with some of their interactions. One model holds that BCL11A participates as part of complexes of transcription factors like those shown to regulate the HbF to HbA switch. KLF1 binds the BCL11A promoter activating its expression and as shown has a dual effect switching by directly on activating HBB while repressing HBG2 and HBG1 indirectly by activating BCL11A. The cartoon does not illustrate the 3 dimensional interactions and the chromosome dynamics that include histone modification and methylation of critical regions of the HBB gene cluster.that are integral components of the transcription process. (Figure provided by and adapted from Orkin, SH, From GWAS-identified locus to reversing the fetal hemoglobin switch: Functional and genetic validation, in, Genomics: Gene discovery and clinical applications for cardiovascular, lung, and blood diseases. Sept. 2011, NIH, Bethesda, MD)

Back to article page