A functional screen for Krüppel-like factors that regulate the human gamma-globin gene through the CACCC promoter element.
Krüppel-like factors (KLFs) have been systematically screened as potential candidates to regulate human gamma-globin gene expression through its CACCC element. Initially, 21 human proteins that have close sequence similarity to EKLF/KLF1, a known regulator of the human beta-globin gene, were identified. The phylogenetic relationship of these 22 KLF/Sp1 proteins was determined. KLF2/LKLF, KLF3/BKLF, KLF4/GKLF, KLF5/IKLF, KLF8/BKLF3, KLF11/FKLF, KLF12/AP-2rep and KLF13/FKLF2 were chosen for functional screening. Semi-quantitative RT-PCR demonstrated that all eight of these candidates are present in human erythroid cell lines, and that the expression of the KLF2, 4, 5 and 12 mRNAs changed significantly upon erythroid differentiation. Each of the eight KLF mRNAs is expressed in mouse erythroid tissues, throughout development. UV cross-linking assays suggest that multiple erythroid proteins from human cell lines and chicken primary cells interact with the gamma-globin CACCC element. In co-transfection assays in K562 cells, it was demonstrated that KLF2, 5 and 13 positively regulate, and KLF8 negatively regulates, the gamma-globin gene through the CACCC promoter element. The data collectively suggest that multiple KLFs may participate in the regulation of gamma-globin gene expression and that KLF2, 5, 8 and 13 are prime candidates for further study.
Zhang
Ping
P
Department of Human Genetics, Virginia Commonwealth University, PO Box 980033, 1101 E. Marshall Street, Richmond, VA 23298-0033, USA.
Basu
Priyadarshi
P
Redmond
Latasha C
LC
Morris
Pamela E
PE
Rupon
Jeremy W
JW
Ginder
Gordon D
GD
Lloyd
Joyce A
JA
D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics; D002645:Chickens; D004268:DNA-Binding Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D005914:Globins / Q000235:genetics*; D006801:Humans; D020014:K562 Cells; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D051379:Mice; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology; D014162:Transfection
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C486423:KLF13 protein, human; C096161:KLF2 protein, human; C000715467:KLF4 protein, human; C492214:KLF5 protein, human; C507402:KLF8 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D012333:RNA, Messenger; D012097:Repressor Proteins; C080774:erythroid Kruppel-like factor; D005914:Globins