Differential regulation of the alpha-globin locus by Kruppel-like factor 3 in erythroid and non-erythroid cells

作者：Funnell Alister P W; Vernimmen Douglas; Lim Wooi F; Mak Ka Sin; Wienert Beeke; Martyn Gabriella E; Artuz Cri**el M; Burdach Jon; Quinlan Kate G R; Higgs Douglas R; Whitelaw Emma; Pearson Richard C M; Crossley Merlin^*

来源：BMC Molecular Biology, 2014, 15(1): 8.

DOI：10.1186/1471-2199-15-8

• KLF1
• KLF3
• Alpha globin
• Globin gene regulation
• Transcription factor

Background: Kruppel-like Factor 3 (KLF3) is a broadly expressed zinc-finger transcriptional repressor with diverse biological roles. During erythropoiesis, KLF3 acts as a feedback repressor of a set of genes that are activated by Kruppel-like Factor 1 (KLF1). Noting that KLF1 binds alpha-globin gene regulatory sequences during erythroid maturation, we sought to determine whether KLF3 also interacts with the alpha-globin locus to regulate transcription. %26lt;br%26gt;Results: We found that expression of a human transgenic alpha-globin reporter gene is markedly up-regulated in fetal and adult erythroid cells of Klf3(-/-) mice. Inspection of the mouse and human alpha-globin promoters revealed a number of canonical KLF-binding sites, and indeed, KLF3 was shown to bind to these regions both in vitro and in vivo. Despite these observations, we did not detect an increase in endogenous murine alpha-globin expression in Klf3(-/-) erythroid tissue. However, examination of murine embryonic fibroblasts lacking KLF3 revealed significant de-repression of a-globin gene expression. This suggests that KLF3 may contribute to the silencing of the alpha-globin locus in non-erythroid tissue. Moreover, ChIP-Seq analysis of murine fibroblasts demonstrated that across the locus, KLF3 does not occupy the promoter regions of the alpha-globin genes in these cells, but rather, binds to upstream, DNase hypersensitive regulatory regions. %26lt;br%26gt;Conclusions: These findings reveal that the occupancy profile of KLF3 at the alpha-globin locus differs in erythroid and non-erythroid cells. In erythroid cells, KLF3 primarily binds to the promoters of the adult alpha-globin genes, but appears dispensable for normal transcriptional regulation. In non-erythroid cells, KLF3 distinctly binds to the HS-12 and HS-26 elements and plays a non-redundant, albeit modest, role in the silencing of alpha-globin expression.

• 出版日期2014-5-16