Wnt signaling has emerged as a major regulator of tissue development by governing the self-renewal and maintenance of stem cells in most tissue types. As a key upstream regulator of the Wnt pathway, the transmembrane E3 ligase ZNRF3 has recently been established to play a role in negative regulation of Wnt signaling by targeting Frizzled (FZD) receptor for ubiquitination and degradation. However, the upstream regulation of ZNRF3, in particular the turnover of ZNRF3, is still unclear. Here we report that ZNRF3 is accumulated in the presence of proteasome inhibitor treatment independent of its E3-ubiquitin ligase activity. Furthermore, the Cullin 1-specific SCF complex containing β-TRCP has been identified to directly interact with and ubiquitinate ZNRF3 thereby regulating its protein stability. Similar with the degradation of β-catenin by β-TRCP, ZNRF3 is ubiquitinated by β-TRCP in both CKI-phosphorylation- and degron-dependent manners. Thus, our findings not only identify a novel substrate for β-TRCP oncogenic regulation, but also highlight the dual regulation of Wnt signaling by β-TRCP in a context-dependent manner where β-TRCP negatively regulates Wnt signaling by targeting β-catenin, and positively regulates Wnt signaling by targeting ZNRF3.
Cells, Cultured ; Humans ; Proteolysis ; Ubiquitin-Protein Ligases ; metabolism ; Ubiquitination ; beta-Transducin Repeat-Containing Proteins ; metabolism

GLP-1 (glucagon like peptide-1) is new anti-diabetic drug with a number of beneficial effects. It stimulates glucose dependant insulin secretion and restoration of beta cell mass through enhancement of islet mass. However, it is easily inactivated after being secreted from enteroendocrine L cells. Recent trial to increased GLP-1 is to directly stimulate L cells through its receptor located in the surface of L cell. Taste receptor in the apical surface of L cell is activated by various tastants contained in the food. Tongue perceives taste sense through the heterotrimeric G-protein (alpha-gustducin) and its downstream signaling cascades. Same taste receptors are also expressed in enteroendocrine cells. In duodenal L cell, alpha-gustducin was detected by immunofluorescence stainig at the luminal projections of enteroendocrine cells. And several other taste signaling elements were also found in L cells. Ingestion of sweet or bitter compounds revealed stimulation of GLP-1 secretion and the regulation of plasma insulin and glucose. In this review, I will briefly introduce the possibilities to stimulate GLP-1 secretion though the membrane receptor in enteroendocrine cell. And it will be the good candidate to develop the treatment modality for obesity, diabetes and abnormal gut motility.
Eating ; Enteroendocrine Cells ; Fluorescent Antibody Technique ; Glucagon ; Glucagon-Like Peptide 1 ; Glucose ; GTP-Binding Proteins ; Insulin ; Membranes ; Obesity ; Phenobarbital ; Plasma ; Tongue ; Transducin

OBJECTIVE: To develop a multiplex PCR method for a rapid detection of Y chromosome-specific sequences in patients with Turner syndrome. METHODS: Nine genes were selected from various regions of the Y chromosome for designing the primers, which included SRY, TBL1Y, TSPY on the short arm of the Y chromosome, DDX3Y, HSFY1, RPS4Y2 and CDY1 on the long arm of Y chromosome and SHOX in the short arm and SPRY3 in the long arm of the pseudoautosomal region (PAR) of X and Y chromosomes. A multiplex PCR method for the nine genes in Y chromosome was established and optimized. The sensitivity was tested by using different amounts of genomic DNA. A total of 36 patients with Turner syndrome and a patient with male dwarfism with karyotype of 46, X, +mar were examined by the multiplex PCR method for the existence of materials from the Y chromosome. RESULTS: The optimization results of the multiplex PCR reaction system (50 μL) showed that when the final concentration of upstream and downstream of each pair of primers was 0.1 μM, the multiplex PCR reaction of the 9 pairs of primers clearly amplified the target with the expected band size, and there was no non-specific amplification. The bands were clearly visible when the amount of genomic DNA in the multiple PCR reaction system was as low as 1 ng. By using the method, we have examined the 36 patients with Turner syndrome. One patient with Turner syndrome with karyotype of 45,X[40]/47XYY[21] amplified specific seven genes on Y chromosome, 35 patients with Turner syndrome amplified only two target genes SHOX and SPRY3, but not the other seven specific genes on the Y chromosome, which was in keeping with the clinical manifestations of such patients. CONCLUSION This study established a multiplex PCR reaction system with nine genes, which can quickly and accurately screen Y chromosome materials in patients with Turner syndrome. It has the advantages of low cost, simple operation, high specificity and rapid turn-around time, and can be used to detect Turner syndrome patients with Y chromosome material in time. The method has provided a diagnostic basis for preventive gonad resection to prevent malignant gonadal tumors.
Humans ; Male ; Turner Syndrome/genetics* ; Multiplex Polymerase Chain Reaction ; Y Chromosome ; Karyotyping ; DNA Primers ; DNA ; Chromosomes, Human, Y/genetics* ; Transducin/genetics* ; Minor Histocompatibility Antigens ; DEAD-box RNA Helicases/genetics*

OBJECTIVETo employ single nucleotide polymorphisms (SNP) microarray to detect copy number variations (CNVs) for the diagnosis of disease and molecular classification.

METHODSFor a patient with split-hand/split-foot malformation, genome-wide copy number variants SNP microarray was applied. Tiny copy number variations were verified by real-time fluorescent quantitative PCR.

RESULTSThe results of SNP microarray has revealed that the patient has carried a 0.39 Mb duplication in 10q24.31-24.32 (102 955 122-103 348 688), which has encompassed genes including LBX1, BTRC and POLL. By real-time fluorescent quantitative PCR, duplicate area encompassing the pathogenic genes have been verified. The results for LBX1, BTRC, POLL genes were all consistent with the SNP microarray test. Moreover, a duplication was detected in exon 9 of FBXW4 gene which is in nearby.

CONCLUSIONSNP chips can efficiently identify tiny CNVs (< 1.0 Mb). In combination with real-time fluorescence quantitative PCR, this may provide valuable information for prenatal diagnosis.

Adult ; Asian Continental Ancestry Group ; genetics ; China ; Chromosome Duplication ; DNA Copy Number Variations ; DNA Polymerase beta ; genetics ; Homeodomain Proteins ; genetics ; Humans ; Limb Deformities, Congenital ; genetics ; Male ; Polymorphism, Single Nucleotide ; Transcription Factors ; genetics ; beta-Transducin Repeat-Containing Proteins ; genetics

Exposure to light can induce photoreceptor cell death and exacerbate retinal degeneration. In this study, mice with genetic knockout of several genes, including rhodopsin kinase (Rhok-/-), arrestin (Sag-/-), transducin (Gnat1-/-), c-Fos (c-Fos-/-) and arrestin/transducin (Sag-/-/Gnat1-/-), were examined. We measured the expression levels of thousands of genes in order to investigate their roles in phototransduction signaling in light-induced retinal degeneration using DNA microarray technology and then further explored the gene network using pathway analysis tools. Several cascades of gene components were induced or inhibited as a result of corresponding gene knockout under specific light conditions. Transducin deletion blocked the apoptotic signaling induced by exposure to low light conditions, and it did not require c-Fos/AP-1. Deletion of c-Fos blocked the apoptotic signaling induced by exposure to high intensity light. In the present study, we identified many gene transcripts that are essential for the initiation of light-induced rod degeneration and proposed several important networks that are involved in pro- and anti-apoptotic signaling. We also demonstrated the different cascades of gene components that participate in apoptotic signaling under specific light conditions.
Animals ; Apoptosis/radiation effects ; G-Protein-Coupled Receptor Kinase 1/genetics ; GTP-Binding Protein alpha Subunits/genetics ; *Gene Expression Profiling ; Genes, fos/genetics ; Light/adverse effects ; Light Signal Transduction/*genetics/physiology/radiation effects ; Mice ; Mice, Knockout ; Oligonucleotide Array Sequence Analysis ; Retina/metabolism/pathology/radiation effects ; Retinal Degeneration/etiology/*genetics/physiopathology ; Transducin/genetics

An F-box protein, beta-TrCP recognizes substrate proteins and destabilizes them through ubiquitin-dependent proteolysis. It regulates the stability of diverse proteins and functions as either a tumor suppressor or an oncogene. Although the regulation by beta-TrCP has been widely studied, the regulation of beta-TrCP itself is not well understood yet. In this study, we found that the level of beta-TrCP1 is downregulated by various protein kinase inhibitors in triple-negative breast cancer (TNBC) cells. A PI3K/mTOR inhibitor PI-103 reduced the level of beta-TrCP1 in a wide range of TNBC cells in a proteasome-dependent manner. Concomitantly, the levels of c-Myc and cyclin E were also downregulated by PI-103. PI-103 reduced the phosphorylation of beta-TrCP1 prior to its degradation. In addition, knockdown of beta-TrCP1 inhibited the proliferation of TNBC cells. We further identified that pharmacological inhibition of mTORC2 was sufficient to reduce the beta-TrCP1 and c-Myc levels. These results suggest that mTORC2 regulates the stability of beta-TrCP1 in TNBC cells and targeting beta-TrCP1 is a potential approach to treat human TNBC.
Cell Line, Tumor ; Cell Proliferation ; Cell Survival/drug effects ; Cyclin E/genetics/metabolism ; Dose-Response Relationship, Drug ; Female ; Furans/pharmacology ; Gene Knockdown Techniques ; Humans ; Models, Biological ; Multiprotein Complexes/antagonists & inhibitors ; Phosphatidylinositol 3-Kinases/*antagonists & inhibitors ; Phosphorylation/drug effects ; Protein Kinase Inhibitors/*pharmacology ; Proteolysis/drug effects ; Proto-Oncogene Proteins c-myc/genetics/metabolism ; Pyridines/pharmacology ; Pyrimidines/pharmacology ; TOR Serine-Threonine Kinases/*antagonists & inhibitors ; Triple Negative Breast Neoplasms/genetics/*metabolism ; beta-Transducin Repeat-Containing Proteins/genetics/*metabolism