Acetylation-Mimic Mutation of TRIM28-Lys304 to Gln Attenuates the Interaction with KRAB-Zinc-Finger Proteins and Affects Gene Expression in Leukemic K562 Cells.

TRIM28/KAP1/TIF1β is a crucial epigenetic modifier. Genetic ablation of is embryonic lethal, although RNAi-mediated knockdown in somatic cells yields viable cells. Reduction in TRIM28 abundance at the cellular or organismal level results in polyphenism.

Generation of TRIM28 Knockout K562 Cells by CRISPR/Cas9 Genome Editing and Characterization of TRIM28-Regulated Gene Expression in Cell Proliferation and Hemoglobin Beta Subunits.

TRIM28 is a scaffold protein that interacts with DNA-binding proteins and recruits corepressor complexes to cause gene silencing. TRIM28 contributes to physiological functions such as cell growth and differentiation. In the chronic myeloid leukemia cell line K562, we edited using CRISPR/Cas9 technology, and the complete and partial knockout (KO) cell clones were obtained and confirmed using quantitative droplet digital PCR (ddPCR) technology.

The functional characterization of phosphorylation of tristetraprolin at C-terminal NOT1-binding domain.

Background: Tristetraprolin (TTP) family proteins contain conserved tandem CCCH zinc-finger binding to AU-rich elements and C-terminal NOT1-binding domain. TTP is phosphorylated extensively in cells, and its mRNA destabilization activity is regulated by protein phosphorylation.

Methods: We generated an antibody against phospho-Serine316 located at the C-terminal NOT1-binding site and examined TTP phosphorylation in LPS-stimulated RAW264.

TRIM28 Regulates Dlk1 Expression in Adipogenesis.

The tripartite motif-containing protein 28 (TRIM28) is a transcription corepressor, interacting with histone deacetylase and methyltransferase complexes. TRIM28 is a crucial regulator in development and differentiation. We would like to investigate its function and regulation in adipogenesis.

The molecular genetic background leading to the formation of the human erythroid-specific Xg/CD99 blood groups.

The Xg and CD99 antigens of the human Xg blood group system show a unique and sex-specific phenotypic relationship. The phenotypic relationship is believed to result from transcriptional coregulation of the and genes, which span the pseudoautosomal boundary of the X and Y chromosomes. However, the molecular genetic background responsible for these blood groups has remained undetermined.

The differential expression of the blood group P -A4GALT and P -A4GALT alleles is stimulated by the transcription factor early growth response 1.

Background: The P /P phenotypic polymorphism is one of the earliest blood groups discovered in humans. These blood groups have been connected to different levels of expression of the A4GALT gene in P and P red blood cells; however, the detailed molecular genetic mechanism that leads to these two phenotypes has not been established.

Study Design And Methods: After our previous identification of an association between the single-nucleotide polymorphisms (SNPs) rs2143918 and rs5751348 in A4GALT gene and the P /P phenotype, we conduct a survey of transcription factors that might connect these SNPs with the differential expression of the P -A4GALT and P -A4GALT alleles.

A novel function of twins, B subunit of protein phosphatase 2A, in regulating actin polymerization.

Actin is an important component of the cytoskeleton and its polymerization is delicately regulated by several kinases and phosphatases. Heterotrimeric protein phosphatase 2A (PP2A) is a potent phosphatase that is crucial for cell proliferation, apoptosis, tumorigenesis, signal transduction, cytoskeleton arrangement, and neurodegeneration. To facilitate these varied functions, different regulators determine the different targets of PP2A.

Functional regulation of Zfp36l1 and Zfp36l2 in response to lipopolysaccharide in mouse RAW264.7 macrophages.

Background: The tristetraprolin (TTP) family of mRNA-binding proteins contains three major members, Ttp, Zfp36l1, and Zfp36l2. Ttp down-regulates the stability of AU-rich element-containing mRNAs and functions as an anti-inflammation regulator.

Methods: To examine whether other TTP family proteins also play roles in the inflammatory response, their expression profiles and the possible mRNA targets were determined in the knockdown cells.

Phosphorylation of mRNA decapping protein Dcp1a by the ERK signaling pathway during early differentiation of 3T3-L1 preadipocytes.

Background: Turnover of mRNA is a critical step in the regulation of gene expression, and an important step in mRNA decay is removal of the 5' cap. We previously demonstrated that the expression of some immediate early gene mRNAs is controlled by RNA stability during early differentiation of 3T3-L1 preadipocytes.

Methodology/principal Findings: Here we show that the mouse decapping protein Dcp1a is phosphorylated via the ERK signaling pathway during early differentiation of preadipocytes.

Reversible acetylation regulates salt-inducible kinase (SIK2) and its function in autophagy.

Salt-inducible kinase 2 (SIK2) is a serine/threonine protein kinase belonging to the AMP-activated protein kinase (AMPK) family. SIK2 has been shown to function in the insulin-signaling pathway during adipocyte differentiation and to modulate CREB-mediated gene expression in response to hormones and nutrients. However, molecular mechanisms underlying the regulation of SIK2 kinase activity remains largely elusive.

Transcriptional regulation of tristetraprolin by NF-κB signaling in LPS-stimulated macrophages.

Lipopolysaccharide (LPS) treatment causes the marked changes of gene expression in macrophages. Tristetraprolin (TTP), which is an mRNA-destabilizing protein that negatively regulates the expression of pro-inflammatory mediators, is induced by LPS. To delineate the molecular mechanism of LPS-stimulated TTP expression, several inhibitors blocking different signaling pathways were used initially.

Tristetraprolin inhibits poly(A)-tail synthesis in nuclear mRNA that contains AU-rich elements by interacting with poly(A)-binding protein nuclear 1.

Background: Tristetraprolin binds mRNA AU-rich elements and thereby facilitates the destabilization of mature mRNA in the cytosol.

Methodology/principal Findings: To understand how tristetraprolin mechanistically functions, we biopanned with a phage-display library for proteins that interact with tristetraprolin and retrieved, among others, a fragment of poly(A)-binding protein nuclear 1, which assists in the 3'-polyadenylation of mRNA by binding to immature poly(A) tails and thereby increases the activity of poly(A) polymerase, which is directly responsible for polyadenylation. The tristetraprolin/poly(A)-binding protein nuclear 1 interaction was characterized using tristetraprolin and poly(A)-binding protein nuclear 1 deletion mutants in pull-down and co-immunoprecipitation assays.

Differential expression and functional analysis of the tristetraprolin family during early differentiation of 3T3-L1 preadipocytes.

The tristetraprolin (TTP) family comprises zinc finger-containing AU-rich element (ARE)-binding proteins consisting of three major members: TTP, ZFP36L1, and ZFP36L2. The present study generated specific antibodies against each TTP member to evaluate its expression during differentiation of 3T3-L1 preadipocytes. In contrast to the inducible expression of TTP, results indicated constitutive expression of ZFP36L1 and ZFP36L2 in 3T3-L1 preadipocytes and their phosphorylation in response to differentiation signals.

Drosophila eyes absent is a novel mRNA target of the tristetraprolin (TTP) protein DTIS11.

The Tristetraprolin (TTP) protein family includes four mammalian members (TTP, TIS11b, TIS11d, and ZFP36L3), but only one in Drosophila melanogaster (DTIS11). These proteins bind target mRNAs with AU-rich elements (AREs) via two C3H zinc finger domains and destabilize the mRNAs. We found that overexpression of mouse TIS11b or DTIS11 in the Drosophila retina dramatically reduced eye size, similar to the phenotype of eyes absent (eya) mutants.

The protective effects of Lycium barbarum and Chrysanthemum morifolum on diabetic retinopathies in rats.

The effects of Lycium barbarum and Chrysanthemum morifolum extracts on diabetic retinopathy were evaluated. The diabetes model was induced by streptozotocin. Animals were divided into six groups: the control group received only vehicle; diabetic animal models received no treatment, insulin treatment, Lycium extract, Chrysanthemum extract, or a combination of Lycium and Chrysanthemum extracts, respectively.

The role of nocturnin in early adipogenesis and modulation of systemic insulin resistance in human.

The deadenylase nocturnin (Noc, Ccrn4l) has been recently found to regulate lipid metabolism and to control preadipocyte differentiation. Here, we showed that among the five deadenylases tested, Noc and Pan2 exhibited a biphasic expression which is out of phase to each other during adipocyte differentiation of 3T3-L1 cells. The expression levels of other deadenylases, including Parn, Ccr4, and Caf1, were relatively unchanged or reduced.

Phosphorylation alters tau distribution and elongates life span in Drosophila.

The microtubule-associated tau protein has long been considered an axon-specific protein. Although many articles describe the subcellular localization of tau as regulated by post-modification in cultured cells, the intracellular regulation of its distribution in living animals has yet to be elucidated. In the present study, we demonstrate that phosphorylation alters tau polarity in Drosophila melanogaster.

Phosphorylation at Ser473 regulates heterochromatin protein 1 binding and corepressor function of TIF1beta/KAP1.

Background: As an epigenetic regulator, the transcriptional intermediary factor 1beta (TIF1beta)/KAP1/TRIM28) has been linked to gene expression and chromatin remodeling at specific loci by association with members of the heterochromatin protein 1 (HP1) family and various other chromatin factors. The interaction between TIF1beta and HP1 is crucial for heterochromatin formation and maintenance. The HP1-box, PXVXL, of TIF1beta is responsible for its interaction with HP1.

Modulation of immediate early gene expression by tristetraprolin in the differentiation of 3T3-L1 cells.

Tristetraprolin (TTP) is a zinc-finger-containing AU-rich elements (ARE)-binding protein. AREs presented in the 3'untranslated region (UTR) of mRNAs from many proto-oncogenes, cytokines, and growth factors may be targets for regulation of messenger RNA stability. In this study, we observed that many immediate early genes (IEGs) were induced during the early differentiation of 3T3-L1 preadipocytes and their ARE-containing transcripts were degraded rapidly.

Regulation of tristetraprolin during differentiation of 3T3-L1 preadipocytes.

Tristetraprolin is a zinc-finger-containing RNA-binding protein. Tristetraprolin binds to AU-rich elements of target mRNAs such as proto-oncogenes, cytokines and growth factors, and then induces mRNA rapid degradation. It was observed as an immediate-early gene that was induced in response to several kinds of stimulus, such as insulin and other growth factors and stimulators of innate immunity such as lipopolysaccharides.

Secreted frizzled related protein 2 (sFRP2) decreases susceptibility to UV-induced apoptosis in primary culture of canine mammary gland tumors by NF-kappaB activation or JNK suppression.

Tumor formation can result from a decrease in cell death, as well as an increase in cell proliferation. In spite of the high incidence of mammary gland tumors (MGTs) in female dogs, the understanding of its etiology is still poor. Consistent with several proto-oncogenes (such as Wnt) for the mammary gland, sFRP2 is expressed in canine MGTs which is normally silent in the mammary gland.

Differential regulation of ARE-mediated TNFalpha and IL-1beta mRNA stability by lipopolysaccharide in RAW264.7 cells.

Messenger RNA degradation is a mechanism by which eukaryotic cells regulate gene expression and influence cell growth and differentiation. Many protooncogene, cytokine, and growth factor RNAs contain AU-rich element (AREs) in the 3'untranslated regions which enable them to be targeted for rapid degradation. To investigate the mechanism of ARE-mediated RNA stability, we demonstrate the expression and regulation of TNFalpha and IL-1beta mRNAs in LPS-stimulated macrophages.

Secreted frizzled-related protein 2 (SFRP2) is highly expressed in canine mammary gland tumors but not in normal mammary glands.

Canine mammary gland tumor (MGT) is the commonest tumor in female dogs and a good animal model of human breast cancer. A group of newly identified genes encoding secreted frizzled-related proteins (SFRP) have been implicated in apoptosis regulation and tumorigenesis. Canine mammary tissues from 50 spontaneous MGTs and 10 normal mammary glands (MGs) were obtained from surgically excised specimens and analyzed for expression of SFRP2, beta-catenin, and cyclin D1.

Autocrine/paracrine secreted Frizzled-related protein 2 induces cellular resistance to apoptosis: a possible mechanism of mammary tumorigenesis.

Abnormal regulation of apoptosis and cell proliferation is thought to be involved in tumor formation. The secreted Frizzled-related protein 2 (SFRP2) was detected in primary culture of canine mammary gland tumors but not in normal mammary tissues. Thus, to elucidate the role of SFRP2 in mammary tumorigenesis, we overexpressed SFRP2 in mammary gland tumor and MCF7 cells.

Differential activation of a C/EBP beta isoform by a novel redox switch may confer the lipopolysaccharide-inducible expression of interleukin-6 gene.

C/EBP beta, a member of the CCAAT/enhancer binding protein (C/EBP) family, is one of the key transcription factors responsible for the induction of a wide array of genes, some of which play important roles in innate immunity, inflammatory response, adipocyte and myeloid cell differentiation, and the acute phase response. Three C/EBP beta isoforms (i.e.