Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is the master regulatory factor of preadipocyte differentiation. As a result of alternative splicing and alternative promoter usage, PPARγ gene generates multiple transcript variants encoding two protein isoforms. Krüppel-like factor 2 (KLF2) plays a negative role in preadipocyte differentiation. However, its underlying mechanism remains incompletely understood. Here, we demonstrated that KLF2 inhibited the P1 promoter activity of the chicken PPARγ gene. Bioinformatics analysis showed that the P1 promoter harbored a conserved putative KLF2 binding site, and mutation analysis showed that the KLF2 binding site was required for the KLF2-mediated transcription inhibition of the P1 promoter. ChIP, EMSA, and reporter gene assays showed that KLF2 could directly bind to the P1 promoter regardless of methylation status and reduced the P1 promoter activity. Consistently, histone modification analysis showed that H3K9me2 was enriched and H3K27ac was depleted in the P1 promoter upon KLF2 overexpression in ICP1 cells. Furthermore, gene expression analysis showed that KLF2 overexpression reduced the endogenous expression of PPARγ transcript variant 1 (PPARγ1), which is driven by the P1 promoter, in DF1 and ICP1 cells, and that the inhibition of ICP1 cell differentiation by KLF2 overexpression was accompanied by the downregulation of PPARγ1 expression. Taken together, our results demonstrated that KLF2 inhibits chicken preadipocyte differentiation at least inpart via direct downregulation of PPARγ1 expression.
Highlights
Adipose tissue is a depot for energy storage but is the body’s largest endocrine organ and regulates multiple physiological processes by secreting various endocrine and paracrine factors (Ràfols, 2013; Steiner and Lang, 2017; Trim et al, 2018)
These data suggest that Krüppel-like factor 2 (KLF2) negatively regulates P1 promoter activity and that the KLF2 binding site may be located in the +1 to +108 bp region of the P1 promoter
These results indicate that the GAGGCGGTGCC binding site is required for the KLF2-mediated transcription inhibition of the P1 promoter
Summary
Adipose tissue is a depot for energy storage but is the body’s largest endocrine organ and regulates multiple physiological processes by secreting various endocrine and paracrine factors (Ràfols, 2013; Steiner and Lang, 2017; Trim et al, 2018). Preadipocyte differentiation involves a comprehensive network consisting of various transcription factors, such as peroxisome proliferator-activated receptor gamma (PPARγ) (Grimaldi, 2001; Elisabetta et al, 2002; Lee and Kai, 2014), CCAAT/enhancer-binding proteins (C/EBPs) (Tanaka et al, 2014), sterol regulatory element binding proteins (SREBPs) (Madsen et al, 2005), Sp1/Krüppel-like factors (Sp1/KLFs) (Rosen and MacDougald, 2006; Lee et al, 2019), and GATA binding proteins (GATAs) (Rosen and MacDougald, 2006; Lee et al, 2019). KLFs 4, 5, 6, 9, and have been shown to promote preadipocyte differentiation (Dan et al, 2005; Enomoto et al, 2013; Mann et al, 2013; Soroush et al, 2013; Kimura and Fujimori, 2014; Escalona-Nandez et al, 2015), whereas KLFs 2, 3, 7, 10, and inhibit preadipocyte differentiation (Banerjee et al, 2003; Zhang et al, 2013; Wang et al, 2015; Jang et al, 2016; Liu et al, 2018; Sun et al, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
