Direct Promoter Repression by BCL11A Controls the Fetal to Adult Hemoglobin Switch

Cell. 2018 Apr 5;173(2):430-442.e17. doi: 10.1016/j.cell.2018.03.016. Epub 2018 Mar 29.

Abstract

Fetal hemoglobin (HbF, α2γ2) level is genetically controlled and modifies severity of adult hemoglobin (HbA, α2β2) disorders, sickle cell disease, and β-thalassemia. Common genetic variation affects expression of BCL11A, a regulator of HbF silencing. To uncover how BCL11A supports the developmental switch from γ- to β- globin, we use a functional assay and protein binding microarray to establish a requirement for a zinc-finger cluster in BCL11A in repression and identify a preferred DNA recognition sequence. This motif appears in embryonic and fetal-expressed globin promoters and is duplicated in γ-globin promoters. The more distal of the duplicated motifs is mutated in individuals with hereditary persistence of HbF. Using the CUT&RUN approach to map protein binding sites in erythroid cells, we demonstrate BCL11A occupancy preferentially at the distal motif, which can be disrupted by editing the promoter. Our findings reveal that direct γ-globin gene promoter repression by BCL11A underlies hemoglobin switching.

Keywords: BCL11A; CUT&RUN; DNA binding; digital genomic footprinting; gene editing; hemoglobin; protein-binding microarray; repression; zinc finger.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line
  • Chromatin / metabolism
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics
  • Erythroid Cells / cytology
  • Erythroid Cells / metabolism
  • Fetal Hemoglobin / genetics*
  • Gene Editing
  • Humans
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Promoter Regions, Genetic
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Repressor Proteins
  • Zinc Fingers / genetics
  • beta-Globins / genetics
  • beta-Thalassemia / genetics
  • beta-Thalassemia / pathology
  • gamma-Globins / genetics

Substances

  • BCL11A protein, human
  • Carrier Proteins
  • Chromatin
  • Nuclear Proteins
  • Protein Isoforms
  • Repressor Proteins
  • beta-Globins
  • gamma-Globins
  • Fetal Hemoglobin