ABSTRACT
Krüppel-associated box zinc finger proteins (KZFPs) constitute the largest family of mammalian transcription factors, but most remain completely uncharacterized. While initially proposed to primarily repress transposable elements, recent reports have revealed that KFZPs contribute to a wide variety of other biological processes. Using murine and human in vitro and in vivo models, we demonstrate here that one poorly studied KZFP, ZFP30, promotes adipogenesis by directly targeting and activating a retrotransposon-derived Pparg2 enhancer. Through mechanistic studies, we further show that ZFP30 recruits the co-regulator KRAB-associated protein 1 (KAP1), which, surprisingly, acts as a ZFP30 co-activator in this adipogenic context. Our findings provide an understanding of both adipogenic and KZFP-KAP1 complex-mediated gene regulation, showing that the KZFP-KAP1 axis can also function in a non-repressive manner.
Subject(s)
Adipogenesis/genetics , DNA-Binding Proteins/metabolism , Transcription Factors/metabolism , Tripartite Motif-Containing Protein 28/metabolism , Zinc Fingers/physiology , 3T3 Cells , Adipocytes/physiology , Animals , Computational Biology , DNA-Binding Proteins/genetics , Enhancer Elements, Genetic , Female , Gene Expression Regulation/physiology , Gene Knockout Techniques , HEK293 Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , PPAR gamma/genetics , Promoter Regions, Genetic/genetics , Retroelements/genetics , Transcription Factors/geneticsABSTRACT
Adipose tissue is a key determinant of whole body metabolism and energy homeostasis. Unraveling the regulatory mechanisms underlying adipogenesis is therefore highly relevant from a biomedical perspective. Our current understanding of fat cell differentiation is centered on the transcriptional cascades driven by the C/EBP protein family and the master regulator PPARγ. To elucidate further components of the adipogenic gene regulatory network, we performed a large-scale transcription factor (TF) screen overexpressing 734 TFs in mouse pre-adipocytes and probed their effect on differentiation. We identified 22 novel pro-adipogenic TFs and characterized the top ranking TF, ZEB1, as being essential for adipogenesis both in vitro and in vivo. Moreover, its expression levels correlate with fat cell differentiation potential in humans. Genomic profiling further revealed that this TF directly targets and controls the expression of most early and late adipogenic regulators, identifying ZEB1 as a central transcriptional component of fat cell differentiation.
Subject(s)
Adipogenesis/genetics , Gene Regulatory Networks/genetics , Homeodomain Proteins/genetics , Kruppel-Like Transcription Factors/genetics , 3T3-L1 Cells , Adipocytes/cytology , Adipocytes/metabolism , Adipose Tissue/cytology , Adipose Tissue/metabolism , Animals , CCAAT-Enhancer-Binding Protein-beta/genetics , CCAAT-Enhancer-Binding Protein-beta/metabolism , Cell Differentiation/genetics , Cell Line , Cell Nucleus/metabolism , Gene Expression , Homeodomain Proteins/metabolism , Humans , Kruppel-Like Transcription Factors/metabolism , Mice , Mice, Inbred C3H , PPAR gamma/genetics , PPAR gamma/metabolism , Protein Binding , RNA Interference , Signal Transduction/genetics , Transcription Factors/genetics , Transcription Factors/metabolism , Zinc Finger E-box-Binding Homeobox 1ABSTRACT
Chicken intestine harbors a vast number of bacterial strains. In the present study, antimicrobial substance produced by lactic acid bacteria (LAB) isolated from the gastrointestinal tract of healthy chicken was detected, characterized, and purified. Based on 16S rRNA sequencing, the bacteria were identified as Lactobacillus plantarum vN. The antimicrobial substance produced by this bacterium was designated vN-1 and exhibited a broad-spectrum of activity against many important pathogenic and spoilage microorganisms, including Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus luteus, Salmonella Typhimurium, and Erwinia amylovova. vN-1 was determined to be thermostable, insensitive to pH values ranging from 2.0 to 8.0, resistant to various organic solvents and to enzymatic inactivation. The inhibition kinetics displayed a bactericidal mode of action. This study revealed an antimicrobial substance with low molecular mass of less than 1 kDa as determined by ultrafiltration and having features not previously reported for LAB isolated from chicken intestines. The detection of this antimicrobial substance addresses an important aspect of biotechnological control agents of spoilage caused by Pseudomonas spp. and promises the possibility for preservation of refrigerated poultry meat. Practical Application: The newly characterized antimicrobial substance and designated as vN-1 may have the potential to be used in food preservation.