ENU-induced Mutation in the DNA-binding Domain of KLF3 Reveals Important Roles for KLF3 in Cardiovascular Development and Function in Mice

Abstract

KLF3 is a Krüppel family zinc finger transcription factor with widespread tissue expression and no previously known role in heart development. In a screen for dominant mutations affecting cardiovascular function in N-ethyl-N-nitrosourea (ENU) mutagenized mice, we identified a missense mutation in the Klf3 gene that caused aortic valvular stenosis and partially penetrant perinatal lethality in heterozygotes. All homozygotes died as embryos. In the first of three zinc fingers, a point mutation changed a highly conserved histidine at amino acid 275 to arginine (Klf3H275R). This change impaired binding of the mutant protein to KLF3's canonical DNA binding sequence. Heterozygous Klf3H275R mutants that died as neonates had marked biventricular cardiac hypertrophy with diminished cardiac chambers. Adult survivors exhibited hypotension, cardiac hypertrophy with enlarged cardiac chambers, and aortic valvular stenosis. A dominant negative effect on protein function was inferred by the similarity in phenotype between heterozygous Klf3H275R mutants and homozygous Klf3 null mice. However, the existence of divergent traits suggested the involvement of additional interactions. We conclude that KLF3 plays diverse and important roles in cardiovascular development and function in mice, and that amino acid 275 is critical for normal KLF3 protein function. Future exploration of the KLF3 pathway provides a new avenue for investigating causative factors contributing to cardiovascular disorders in humans.

Krüppel-like factors in mammalian stem cells and development

“…Although early observations did not report an embryonic phenotype in Klf3 −/− mice , recent data show that homozygous mutant Klf3 H275R/H275R mice have significant lethality at E14.5-E16.5 (Kelsey et al, 2013). Increased mortality in these mice is likely to be due to heart failure, as the ventricular myocardium and septum are notably thinned and disorganized in these mice (Kelsey et al, 2013).…”

“…Although early observations did not report an embryonic phenotype in Klf3 −/− mice , recent data show that homozygous mutant Klf3 H275R/H275R mice have significant lethality at E14.5-E16.5 (Kelsey et al, 2013). Increased mortality in these mice is likely to be due to heart failure, as the ventricular myocardium and septum are notably thinned and disorganized in these mice (Kelsey et al, 2013). Furthermore, mice harboring heterozygous KLF3 H275R point mutants exhibit increased perinatal lethality with numerous abnormalities in heart morphology at E12.5: marked biventricular myocardial hypertrophy and aortic valve leaflet thickening with adult survivors exhibiting hypotension, aortic valvular stenosis, aortic dilatation, myocardial hypertrophy and increased chamber size (Kelsey et al, 2013).…”

“…Increased mortality in these mice is likely to be due to heart failure, as the ventricular myocardium and septum are notably thinned and disorganized in these mice (Kelsey et al, 2013). Furthermore, mice harboring heterozygous KLF3 H275R point mutants exhibit increased perinatal lethality with numerous abnormalities in heart morphology at E12.5: marked biventricular myocardial hypertrophy and aortic valve leaflet thickening with adult survivors exhibiting hypotension, aortic valvular stenosis, aortic dilatation, myocardial hypertrophy and increased chamber size (Kelsey et al, 2013). It was suggested that the cardiovascular abnormalities in these mice could be attributed to blood pressure dysregulation, because KLF3 is also expressed in the renal vasculature during development (Kelsey et al, 2013).…”

Genome-wide analysis of the zebrafish Klf family identifies two genes important for erythroid maturation

“…By binding to the cofactors (such as CtBP) (Crossley, 1998) that recruit other factors (such as chromatin modifying enzyme (Shi et al, 2003)), Klf3 represses transcription during several significant biological processes, including adipogenesis , B cell development (Turchinovich et al, 2011), erythropoiesis (Crossley et al, 1996), muscle cell development (Haldar et al, 2007) and cardiovascular development (Kelsey et al, 2013). During erythropoiesis, the expression of klf3 is directly regulated by Klf1; Klf3 then represses the expression of non-erythroid genes (Funnell et al, 2012), which might partially contribute to erythroid progenitor differentiation.…”

Krüppel-like Factor 3 (KLF3/BKLF) Is Required for Widespread Repression of the Inflammatory Modulator Galectin-3 (Lgals3)

“…Posttranslational modifications of KLF3 by phosphorylation and sumoylation have also been implicated in enhancing its repressive activity (20,21). KLF3 has been implicated in a host of biological roles spanning from the regulation of B cell development (22) and erythropoiesis (15) to adipogenesis (23,24) and, more recently, in heart function (25).…”