Transcription Factor Erythroid Krüppel-like Factor (ELKF) Is Essential for the Erythropoietin-induced Hemoglobin Production but Not for Proliferation, Viability, or Morphological Maturation

doi:10.1074/jbc.273.37.23793

Transcription Factor Erythroid Krüppel-like Factor (ELKF) Is Essential for the Erythropoietin-induced Hemoglobin Production but Not for Proliferation, Viability, or Morphological Maturation*

From the ^‡Laboratory for Cancer Medicine, Department of Biochemistry, Level 6, MRF Building, Rear, 50 Murray Street, Perth, Western Australia 6001 Australia, ^§Department of Biochemistry, University of Western Australia, Nedlands, Western Australia 6907 Australia, ^¶Department of Biochemistry, University of Sydney, Sydney, New South Wales 2006 Australia, and ^‖The Brookdale Center for Molecular Biology and Department of Biochemistry, Mount Sinai School of Medicine, New York, New York 10029

Abstract

The erythroid Krüppel-like factor (EKLF) is essential for the transcription of β^maj globin in erythroid cells. We show here that RNA for this transcription factor did not alter during erythropoietin-induced differentiation of J2E cells; however, EKLF protein content decreased and was inversely related to globin production. This unexpected result was also observed during chemically induced maturation of two murine erythroleukemia cell lines. To explore the role of EKLF in erythroid terminal differentiation, an antisense EKLF construct was introduced into J2E cells. As a consequence EKLF RNA and protein levels fell by approximately 80%, and the cells were unable to manufacture hemoglobin in response to erythropoietin. The failure to produce hemoglobin was due to reduced transcription of not only globin genes but also key heme enzyme genes. However, numerous other genes, including several erythroid transcription factors, were unaffected by the decrease in EKLF. Although hemoglobin synthesis was severely impaired with depleted EKLF levels, morphological maturation in response to erythropoietin continued normally. Moreover, erythropoietin-induced proliferation and viability were unaffected by the decrease in EKLF levels. We conclude that EKLF affects a specific set of genes, which regulates hemoglobin production and has no obvious effect on morphological changes, cell division, or viability in response to erythropoietin.

Footnotes

↵* This work was supported by National Health and Medical Research Council for NHMRC Grants 96-0581 and 97–0095 and grants from AMRAD and the Cancer Foundation of Western Australia.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵** To whom correspondence should be addressed. Tel.: 61-8-9224-0334; Fax: 61-8-9224-0322.
Abbreviations:

EKLF

erythroid Krüppel-like factor

ALA-S(E)

5-aminolevulinic acid synthase (erythroid)

DAF

diaminofluorene

epo

erythropoietin

FC

ferrochelatase

PBG-D

porphobilinogen deaminase

MEL

murine erythroleukemia

MAP

mitogen-activated protein

BKLF

basic Krüppel-like factor. .
- Received February 27, 1998.
- Revision received June 30, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.