Induction of basic helix-loop-helix protein-containing complexes during erythroid differentiation

James A. Lister, Margaret H. Baron

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The involvement of basic helix-loop-helix (bHLH) transcription factors in erythroid differentiation and development has been established by forced expression of the proteins TALl and Id1 in cultured cell lines and by targeted disruption of the mouse TALl gene. To better understand the mechanism by which bHLH proteins regulate erythropoiesis, we have investigated HLH protein-DNA interactions in mouse erythroleukemia (MEL) cells before and during chemically induced differentiation. Three bHLH (E- box) binding activities were found to be induced in nuclei from differentiating MEL cells. Using specific antisera, we have demonstrated that these complexes are dinners of TALl and ubiquitous E proteins. Similar complexes were detected in nuclear extracts from a human erythroid cell line, K562, and from mouse fetal liver. All three bHLH complexes were disrupted in vitro by Id, a dominant-negative HLH protein that we and others have previously shown to antagonize MEL cell differentiation. During differentiation of an Id1-overexpressing MEL cell line, induction of a complex containing TALl and E2A was not only blocked but reduced below the levels seen in undifferentiating cells. These observations are consistent with the idea that TALI and Id1 have opposing effects on erythroid differentiation and that the level of TALI/E2A heterodimer and/or another E protein-containing complex may influence the decision of a cell to terminally differentiate.

Original languageEnglish
Pages (from-to)25-38
Number of pages14
JournalGene Expression
Volume7
Issue number1
StatePublished - 1998

Keywords

  • Erythroid differentiation
  • Gene regulation
  • Globin switching
  • Helix-loop-helix protein
  • Transcription factors

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