A Positive Regulatory Feedback Loop between EKLF/KLF1 and TAL1/SCL Sustaining the Erythropoiesis

• Main Authors: Chun-Hao Hung, Tung-Liang Lee, Anna Yu-Szu Huang, Kang-Chung Yang, Yu-Chiau Shyu, Shau-Ching Wen, Mu-Jie Lu, Shinsheng Yuan, Che-Kun James Shen
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: International Journal of Molecular Sciences
• Subjects: erythroid differentiation; EKLF/KLF1; gene knockout; TAL1/SCL; global gene expression profiling; direct target genes
• Online Access: https://www.mdpi.com/1422-0067/22/15/8024
• ISSN: 1661-6596; 1422-0067

The erythroid Krüppel-like factor EKLF/KLF1 is a hematopoietic transcription factor binding to the CACCC DNA motif and participating in the regulation of erythroid differentiation. With combined use of microarray-based gene expression profiling and the promoter-based ChIP-chip assay of E14.5 fetal liver cells from wild type (WT) and EKLF-knockout (<i>Eklf</i>^−/−) mouse embryos, we identified the pathways and direct target genes activated or repressed by EKLF. This genome-wide study together with the molecular/cellular analysis of the mouse erythroleukemic cells (MEL) indicate that among the downstream direct target genes of EKLF is <i>Tal1</i>/<i>Scl</i>. <i>Tal1</i>/<i>Scl</i> encodes another DNA-binding hematopoietic transcription factor TAL1/SCL, known to be an <i>Eklf</i> activator and essential for definitive erythroid differentiation. Further identification of the authentic Tal gene promoter in combination with the in vivo genomic footprinting approach and DNA reporter assay demonstrate that EKLF activates the Tal gene through binding to a specific CACCC motif located in its promoter. These data establish the existence of a previously unknow positive regulatory feedback loop between two DNA-binding hematopoietic transcription factors, which sustains mammalian erythropoiesis.