Generation of Mice Deficient in both KLF3/BKLF and KLF8 Reveals a Genetic Interaction and a Role for These Factors in Embryonic Globin Gene Silencing

Abstract

f Krüppel-like factors 3 and 8 (KLF3 and KLF8) are highly related transcriptional regulators that bind to similar sequences of DNA. We have previously shown that in erythroid cells there is a regulatory hierarchy within the KLF family, whereby KLF1 drives the expression of both the Klf3 and Klf8 genes and KLF3 in turn represses Klf8 expression. While the erythroid roles of KLF1 and KLF3 have been explored, the contribution of KLF8 to this regulatory network has been unknown. To investigate this, we have generated a mouse model with disrupted KLF8 expression. While these mice are viable, albeit with a reduced life span, mice lacking both KLF3 and KLF8 die at around embryonic day 14.5 (E14.5), indicative of a genetic interaction between these two factors. In the fetal liver, Klf3 Klf8 double mutant embryos exhibit greater dysregulation of gene expression than either of the two single mutants. In particular, we observe derepression of embryonic, but not adult, globin expression. Taken together, these results suggest that KLF3 and KLF8 have overlapping roles in vivo and participate in the silencing of embryonic globin expression during development.

Mutations in Krüppel-like factor 1 cause transfusion-dependent hemolytic anemia and persistence of embryonic globin gene expression

“…However, it has recently been shown that 2 members of the KLF family (KLF3 and KLF8) may be involved in regulating embryonic globin expression, and a knockout of these 2 transcription factors in erythroid cells de-represses embryonic globin synthesis. 41 Because expression of these 2 factors is driven by KLF1, it is possible that mutations in this protein might reduce KLF3 and KLF8, leading to derepression of embryonic globins. Further analysis of this pathway is warranted because preliminary studies in mice suggest that persistence of embryonic globin expression could ameliorate severe hemoglobinothathies.…”

KLF1-null neonates display hydrops fetalis and a deranged erythroid transcriptome

“…CtBP2 interacts with the N-terminus of KLF3 and related KLFs to provide a repressor function. 71 Mice lacking both Klf3 and Klf8 fail to repress embryonic globin gene expression in vivo, 72 so regulation of CtBP2 could be an alternative mechanism by which KLF1 indirectly regulates embryonic and fetal globin gene silencing (ie, via "enabling" the repression functions of KLF3 and KLF8). We also found that KLF1 regulates SOX6, which plays a key role in definitive erythropoiesis and embryonic globin gene silencing.…”

Kruppel-like transcription factors KLF1 and KLF2 have unique and coordinate roles in regulating embryonic erythroid precursor maturation

“…43,44 KLF8 knockout mice have normal erythroid parameters. 45 The KLF3/KLF8 double knockout causes embryonic lethality, and greater dysregulation of fetal liver gene expression than either single knockout. 45 The reduced number of E10.5 KLF1-/-KLF2-/-peripheral blood cells stems from a defect in erythroid precursor maintenance and maturation.…”

“…45 The KLF3/KLF8 double knockout causes embryonic lethality, and greater dysregulation of fetal liver gene expression than either single knockout. 45 The reduced number of E10.5 KLF1-/-KLF2-/-peripheral blood cells stems from a defect in erythroid precursor maintenance and maturation. Primitive erythroid progenitor colonies (EryP-CFC) derived from E8.5 KLF1-/-embryos are similar in frequency but significantly smaller in size than wild-type.…”