FKLF, a novel Krüppel-like factor that activates human embryonic and fetal beta-like globin genes.
Mol Cell Biol
; 19(5): 3571-9, 1999 May.
Article
em En
| MEDLINE
| ID: mdl-10207080
ABSTRACT
A cDNA encoding a novel Krüppel-type zinc finger protein, FKLF, was cloned from fetal globin-expressing human fetal erythroid cells. The deduced polypeptide sequence composed of 512 amino acids revealed that, like Sp1 and EKLF, FKLF has three contiguous zinc fingers at the near carboxyl-terminal end. A long amino-terminal domain is characterized by the presence of two acidic and two proline-rich regions. Reverse transcription (RT)-PCR assays using various cell lines demonstrated that the FKLF mRNA is expressed predominantly in erythroid cells. FKLF message is detectable by RT-PCR in fetal liver but not in adult bone marrow cells. As predicted from its structural features, FKLF is a transcriptional activator. In luciferase assays FKLF activated the gamma- and epsilon-globin gene promoters, and, to a much lower degree, the beta-globin promoter. Studies of HS2-gamma gene reporter constructs carrying CACCC box deletions revealed that the CACCC box sequence of the gamma gene promoter mediates the activation of the gamma gene by FKLF. Other erythroid promoters (GATA-1, glycophorin B, ferrochelatase, porphobilinogen deaminase, and 5-aminolevulinate synthase) containing CACCC elements or GC-rich potential Sp1-binding sites were activated minimally, if at all, by FKLF, indicating that FKLF is not a general activator of genes carrying the CACCC motifs. Transfection of K562 cells with FKLF cDNA enhanced the expression of the endogenous epsilon- and gamma-globin genes, suggesting an in vivo role of FKLF in fetal and embryonic globin gene expression. Our results indicate that the protein potentially encoded by the FKLF cDNA acts as a transcriptional activator of embryonic and fetal beta-like globin genes.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
/
Fatores de Transcrição
/
Globinas
/
Transativadores
/
Regulação da Expressão Gênica
/
Proteínas de Ciclo Celular
/
Proteínas de Ligação a DNA
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Mol Cell Biol
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Estados Unidos