Phosphorylated MED1 links transcription recycling and cancer growth.

Mediator activates RNA polymerase II (Pol II) function during transcription, but it remains unclear whether Mediator is able to travel with Pol II and regulate Pol II transcription beyond the initiation and early elongation steps. By using in vitro and in vivo transcription recycling assays, we find that human Mediator 1 (MED1), when phosphorylated at the mammal-specific threonine 1032 by cyclin-dependent kinase 9 (CDK9), dynamically moves along with Pol II throughout the transcribed genes to drive Pol II recycling after the initial round of transcription. Mechanistically, MED31 mediates the recycling of phosphorylated MED1 and Pol II, enhancing mRNA output during the transcription recycling process.

Lipolysis drives expression of the constitutively active receptor GPR3 to induce adipose thermogenesis.

Thermogenic adipocytes possess a therapeutically appealing, energy-expending capacity, which is canonically cold-induced by ligand-dependent activation of β-adrenergic G protein-coupled receptors (GPCRs). Here, we uncover an alternate paradigm of GPCR-mediated adipose thermogenesis through the constitutively active receptor, GPR3. We show that the N terminus of GPR3 confers intrinsic signaling activity, resulting in continuous Gs-coupling and cAMP production without an exogenous ligand.

, a Human Plasma Lipid GWAS Locus, Regulates Lipoprotein Metabolism in Mice.

Rationale: Single-nucleotide polymorphisms near the (inflammation and lipid regulator with ubiquitin-associated-like and NBR1 [next to gene 1 protein]-like domains) gene are genome-wide significantly associated with plasma lipid traits and coronary artery disease (CAD), but the biological basis of this association is unknown.

Objective: To investigate the role of ILRUN in plasma lipid and lipoprotein metabolism.

Methods And Results: encodes a protein that contains a ubiquitin-associated-like domain, suggesting that it may interact with ubiquitinylated proteins.

Shared PPARα/γ Target Genes Regulate Brown Adipocyte Thermogenic Function.

Brown adipose tissue (BAT) generates heat to maintain body temperature and suppress obesity. Agonists for nuclear receptors PPARα and PPARγ both affect brown adipocyte function, yet the interplay between these factors in BAT is uncertain. Here, we report that PPARα shares most genomic binding sites with PPARγ, and these common binding sites are more related to BAT function than PPARγ-selective sites without PPARα.

Patient Adipose Stem Cell-Derived Adipocytes Reveal Genetic Variation that Predicts Antidiabetic Drug Response.

Thiazolidinedione drugs (TZDs) target the transcriptional activity of peroxisome proliferator activated receptor γ (PPARγ) to reverse insulin resistance in type 2 diabetes, but side effects limit their clinical use. Here, using human adipose stem cell-derived adipocytes, we demonstrate that SNPs were enriched at sites of patient-specific PPARγ binding, which correlated with the individual-specific effects of the TZD rosiglitazone (rosi) on gene expression. Rosi induction of ABCA1, which regulates cholesterol metabolism, was dependent upon SNP rs4743771, which modulated PPARγ binding by influencing the genomic occupancy of its cooperating factor, NFIA.

Interrogation of nonconserved human adipose lincRNAs identifies a regulatory role of in adipocyte metabolism.

Long intergenic noncoding RNAs (lincRNAs) have emerged as important modulators of cellular functions. Most lincRNAs are not conserved among mammals, raising the fundamental question of whether nonconserved adipose-expressed lincRNAs are functional. To address this, we performed deep RNA sequencing of gluteal subcutaneous adipose tissue from 25 healthy humans.

Heterozygous Deletion Impacting SMARCAD1 in the Original Kindred with Absent Dermatoglyphs and Associated Features (Baird, 1964).

In 1964, Baird described a family with adermatoglyphia, facial milia, and skin fragility. Using whole exome sequencing, genotyping, and Sanger sequencing, we identified a 116-kb heterozygous deletion involving exons 1-9 of SMARCAD1 in descendants of this kindred. This contrasts with point mutations within exon 9 in all other reported families.

Targeting PPARγ in the epigenome rescues genetic metabolic defects in mice.

Obesity causes insulin resistance, and PPARγ ligands such as rosiglitazone are insulin sensitizing, yet the mechanisms remain unclear. In C57BL/6 (B6) mice, obesity induced by a high-fat diet (HFD) has major effects on visceral epididymal adipose tissue (eWAT). Here, we report that HFD-induced obesity in B6 mice also altered the activity of gene regulatory elements and genome-wide occupancy of PPARγ.

PARP-1 Controls the Adipogenic Transcriptional Program by PARylating C/EBPβ and Modulating Its Transcriptional Activity.

Poly(ADP-ribosyl)ation (PARylation) is a post-translational modification of proteins mediated by PARP family members, such as PARP-1. Although PARylation has been studied extensively, few examples of definitive biological roles for site-specific PARylation have been reported. Here we show that C/EBPβ, a key pro-adipogenic transcription factor, is PARylated by PARP-1 on three amino acids in a conserved regulatory domain.

Genetic Variation Determines PPARγ Function and Anti-diabetic Drug Response In Vivo.

SNPs affecting disease risk often reside in non-coding genomic regions. Here, we show that SNPs are highly enriched at mouse strain-selective adipose tissue binding sites for PPARγ, a nuclear receptor for anti-diabetic drugs. Many such SNPs alter binding motifs for PPARγ or cooperating factors and functionally regulate nearby genes whose expression is strain selective and imbalanced in heterozygous F1 mice.

GENE REGULATION. Discrete functions of nuclear receptor Rev-erbα couple metabolism to the clock.

Circadian and metabolic physiology are intricately intertwined, as illustrated by Rev-erbα, a transcription factor (TF) that functions both as a core repressive component of the cell-autonomous clock and as a regulator of metabolic genes. Here, we show that Rev-erbα modulates the clock and metabolism by different genomic mechanisms. Clock control requires Rev-erbα to bind directly to the genome at its cognate sites, where it competes with activating ROR TFs.

Thiazolidinediones and the promise of insulin sensitization in type 2 diabetes.

Type 2 diabetes is caused by insulin resistance coupled with an inability to produce enough insulin to control blood glucose, and thiazolidinediones (TZDs) are the only current antidiabetic agents that function primarily by increasing insulin sensitivity. However, despite clear benefits in glycemic control, this class of drugs has recently fallen into disuse due to concerns over side effects and adverse events. Here we review the clinical data and attempt to balance the benefits and risks of TZD therapy.

Acetylation-defective mutant of Pparγ is associated with decreased lipid synthesis in breast cancer cells.

In our prior publications we characterized a conserved acetylation motif (K(R)xxKK) of evolutionarily related nuclear receptors. Recent reports showed that peroxisome proliferator activated receptor gamma (PPARγ) deacetylation by SIRT1 is involved in delaying cellular senescence and maintaining the brown remodeling of white adipose tissue. However, it still remains unknown whether lysyl residues 154 and 155 (K154/155) of the conserved acetylation motif (RIHKK) in Pparγ1 are acetylated.

Species-specific strategies underlying conserved functions of metabolic transcription factors.

The winged helix protein FOXA2 and the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) are highly conserved, regionally expressed transcription factors (TFs) that regulate networks of genes controlling complex metabolic functions. Cistrome analysis for Foxa2 in mouse liver and PPARγ in mouse adipocytes has previously produced consensus-binding sites that are nearly identical to those used by the corresponding TFs in human cells. We report here that, despite the conservation of the canonical binding motif, the great majority of binding regions for FOXA2 in human liver and for PPARγ in human adipocytes are not in the orthologous locations corresponding to the mouse genome, and vice versa.

Clinical, genetic, and functional characterization of four patients carrying partial loss-of-function mutations in the steroidogenic acute regulatory protein (StAR).

Context: Nonclassic congenital lipoid adrenal hyperplasia (lipoid CAH) is a recently recognized disorder caused by mutations in the steroidogenic acute regulatory protein (StAR) that retain partial function. Affected individuals can present with a phenotype of late onset adrenal insufficiency with only mild or minimally disordered sexual development.

Objectives: The aim was to delineate the clinical spectrum of StAR mutations and correlate phenotype with StAR activity.

Differential gene regulation of StarD4 and StarD5 cholesterol transfer proteins. Activation of StarD4 by sterol regulatory element-binding protein-2 and StarD5 by endoplasmic reticulum stress.

The StarD4 and StarD5 proteins share approximately 30% identity, and each is a steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domain. We previously showed StarD4 expression is sterol-repressed, consistent with regulation by sterol regulatory element-binding proteins (SREBPs), whereas StarD5 is not sterol-regulated. Here we further address the regulation and function of StarD4 and StarD5.

Intracellular cholesterol transport.

Intracellular cholesterol transport is essential for the maintenance of cholesterol homeostasis. Many aspects of cholesterol metabolism are well-known, including its synthesis in the endoplasmic reticulum, its extracellular transport in plasma lipoproteins, its uptake by the low-density lipoprotein receptor, and its regulation of SREBP and LXR transcription factors. These fundamental pathways in cholesterol metabolism all rely on its proper intracellular distribution among subcellular organelles and the plasma membrane.

Cholesterol feeding of mice expressing cholesterol 7alpha-hydroxylase increases bile acid pool size despite decreased enzyme activity.

Dietary cholesterol regulation of cholesterol 7alpha-hydroxylase (Cyp7a1), the rate-limiting enzyme in the classical pathway of bile acid synthesis, has been implicated in plasma cholesterol responsiveness. In the current study, the effects of 0.0% and 0.

Effects of simvastatin on plasma lipoproteins and response to arterial injury in wild-type and apolipoprotein-E-deficient mice.

Objective: To test the non-lipid-lowering effects of simvastatin on the response to injury in normolipidemic and hyperlipidemic mice.

Methods And Results: Wild-type (WT) mice (n = 40) and hyperlipidemic apolipoprotein-E-deficient (apoE(-/-)) mice (n = 40) received normal chow or chow containing simvastatin 100 mg/kg/day prior to bilateral femoral artery wire injury. Intimal hyperplasia and plasma cholesterol concentration were quantified after 4 weeks.

Novel putative SREBP and LXR target genes identified by microarray analysis in liver of cholesterol-fed mice.

High-cholesterol diets elicit changes in gene expression via such transcription factors as sterol-regulatory element binding proteins (SREBPs) and liver X receptors (LXRs). We used Affymetrix microarrays to identify genes in mouse liver regulated by dietary cholesterol (0.0% vs.

Crystal structure of the Mus musculus cholesterol-regulated START protein 4 (StarD4) containing a StAR-related lipid transfer domain.

The x-ray structure of the mouse cholesterol-regulated START protein 4 (StarD4) has been determined at 2.2-A resolution, revealing a compact alpha/beta structure related to the START domain present in the cytoplasmic C-terminal portion of human MLN64. The volume of the putative lipid-binding tunnel was estimated at 847 A(3), which is consistent with the binding of one cholesterol-size lipid molecule.