👤 Mujie Ye

START-dependent transcription in Saccharomyces cerevisiae is regulated by two transcription factors SBF and MBF, whose activity is controlled by the binding of the repressor Whi5. Phosphorylation and removal of Whi5 by the cyclin-dependent kinase (CDK) Cln3-Cdc28 alleviates the Whi5-dependent repression on SBF and MBF, initiating entry into a new cell cycle. This Whi5-SBF/MBF transcriptional circuit is analogous to the regulatory pathway in mammalian cells that features the E2F family of G1 transcription factors and the retinoblastoma tumor suppressor protein (Rb). Here we describe genetic and biochemical evidence for the involvement of another CDK, Pcl-Pho85, in regulating G1 transcription, via phosphorylation and inhibition of Whi5. We show that a strain deleted for both PHO85 and CLN3 has a slow growth phenotype, a G1 delay, and is severely compromised for SBF-dependent reporter gene expression, yet all of these defects are alleviated by deletion of WHI5. Our biochemical and genetic tests suggest Whi5 mediates repression in part through interaction with two histone deacetylases (HDACs), Hos3 and Rpd3. In a manner analogous to cyclin D/CDK4/6, which phosphorylates Rb in mammalian cells disrupting its association with HDACs, phosphorylation by the early G1 CDKs Cln3-Cdc28 and Pcl9-Pho85 inhibits association of Whi5 with the HDACs. Contributions from multiple CDKs may provide the precision and accuracy necessary to activate G1 transcription when both internal and external cues are optimal. Show less

E3 ubiquitin ligases, which target specific molecules for proteolytic destruction, have emerged as key regulators of immune functions. Several E3 ubiquitin ligases, including c-Cbl, Cbl-b, GRAIL, Itch, and Nedd4, have been shown to negatively regulate T-cell activation. Here, we report that the HECT-type E3 ligase AIP2 positively regulates T-cell activation. Ectopic expression of AIP2 in mouse primary T cells enhances their proliferation and interleukin-2 production by suppressing the apoptosis of T cells. AIP2 interacts with and promotes ubiquitin-mediated degradation of EGR2, a zinc finger transcription factor that has been found to regulate Fas ligand (FasL) expression during activation-induced T-cell death. Suppression of AIP2 expression by small RNA interference upregulates EGR2, inhibits EGR2 ubiquitination and FasL expression, and enhances the apoptosis of T cells. Therefore, AIP2 regulates activation-induced T-cell death by suppressing EGR2-mediated FasL expression via the ubiquitin pathway. Show less

To clarify the differential expression of the genes related to the lipid metabolism in the early stage of atherosclerosis in the young LDLR-/- mice of different ages. A RT-PCR assay was used to analyse the gene expression patterns in the livers of LDLR-/- mice and wild type (WT) mice from 14 to 90 days. The characteristics of early lipid deposition in intima were evaluated using biochemical and pathological techniques. In LDLR-/- mice, when compared to WT mice, the mRNA level of the apolipoprotein A IV (apoA IV), fatty acid translocase (Fat/CD36) and carnitine palmitoyl transferase I (CPT I) changed prominently at the age of 14-days (P < 0.05). At 30 days, the mRNA level of apolipoprotein A I (apoA I) was up regulated, but apolipoprotein F (apoF), CD36 and CPT I were down regulated (P < 0.05). At 60 days, the mRNA levels of apoA I, CPT I and liver X receptor alpha (LXRalpha) were up regulated, but apoA IV was down regulated (P < 0.05). At 90 days, the level of the apoA I was higher, but the expression of the apoA IV, apoF and acyl-coenzymeA oxidase 1 (ACOX1) were down regulated (P < 0.05), whereas the expression of apolipoprotein A V (apoA V), apolipoprotein E (apoE), peroxidase proliferator-activated receptor alpha (PPARalpha) and angiopoietin-like protein 3 (angptl 3) had no significant changes (P > 0.05). The serum levels of TC (P < 0.05), TG (P < 0.05) and LDLC (P < 0.05) in LDLR-/- mice were significantly higher than those in wild type mice with the same age. The mRNA levels of the apoA I, apoA IV, apoF, FAT/CD36, CPT I, ACOX1 and LXRalpha of the LDLR-/- mice were significantly changed compared to the WT mice. The genes may be of some relevance to the complicated lipid metabolism network, and have effect in the early stage of atherogenesis. Show less

The work was aimed to investigate the differential expressions of lipid metabolism related genes in the early stage of atherosclerosis in the young apolipoprotein E deficient (apoE(-/-)) mice at different ages with normal chow diet. The genotypes of mice were identified by using multiplex polymerase chain reaction (multi-PCR) analysis. The semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR were used to analyze the expressions of lipid metabolism related genes in the liver of apoE(-/-) and age-matched wild type (WT) mice of 14-day old, 1-month old, 2-month old, 3-month old. The serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) contents were assayed using COD-PAP and GPO-PAP methods. The serum apolipoprotein B100 (apoB100) content was quantitated by immune turbidimetry. The hearts were perfusion-fixed in 4% formaldehyde, infiltrated with 30% gum sucrose for 24 h at 4 °C, and embedded in OCT compound. The aortic sinus tissues were serially sectioned at -15 °C, stained with Sudan IV, and counterstained with light green. The results were shown as follows. Compared with that in WT mice, the mRNA levels of apoA I and apoA IV in apoE(-/-) mice aged from 14-day old to 3-month old changed prominently (P<0.05), with apoA I up-regulated and apoA IV down-regulated. At the age of 1 month, the expression of apoB100 in apoE(-/-) mice was higher than that in WT mice (P<0.05). The expression of apoA V was up-regulated (P<0.05) and there was obvious lipid deposition in the aortic intima in apoE(-/-) mice at the age of 2 months. The expressions of fatty acid translocase (Fat/CD36) and angiopoietin-like protein 3 (Angptl 3) in apoE(-/-) mice were higher than those in WT mice at the age of 3 months (P<0.05), while the expressions of peroxisome proliferator-activated receptor α (PPARα), liver X receptor α (LXRα), carnitine palmitoyl transferase I (CPT I) and acyl coenzyme A oxidase 1 (ACOX1) showed no significant changes. The serum TC, TG, LDL-C and HDL-C contents in apoE(-/-) mice aged from 14-day old to 3-month old were higher than those in age-matched WT mice. apoE(-/-) mice showed a marked increase in serum apoB100 content, consistent with the trend of serum LDL-C content and apoB100 mRNA content in the liver. The results suggest that the mRNA expressions of apoA I, apoA IV, apoA V, apoB100 and Angptl 3 in apoE(-/-) mice change significantly compared with those in WT mice, and these genes might be relevant to the complicated lipid metabolism network, and involved in the early stage of atherogenesis. Show less

To compare the molecular basis difference between recurrent respiratory papillomatosis (RRP) and vocal cord polyp, to analyze the expression of glycan structural genes, and to discuss the pathopoiesis mechanism of RRP. The gene expressing profile between the 3 groups papilloma and the vocal cord polyp regarded as normal larynx epithelium were compared using mRNA parallel amplify and the human genome gene expressing microarray. Through cluster analysis, Gene Ontology function gene annotation and path way analysis, the relative gene of RRP and HPV infection were acquired. According to three microarrays results, total 567 expression changed genes related to HPV induce RRP were acquired. A serial change of glycan structure biosynthesis and degradation pathways was significant. The expression of dolichyl-phosphate mannosyltransferase polypeptide 1 (DPM1), asparagine-linked glycosylation 1 homolog (ALG1), fucosyltransferase 8 (FUT8) and alpha-mannosidase 1A (MAN1A) were regulated and beta-hexosaminidase (HEXB), beta1-galactosidase (GLB1), exostoses 1 (EXT1), fucosyltransferase (FUT) reduced expression and heparan sulfate 3-O-sulfotransferase 1 (HS3ST3A1) increased expression. The two related enzymes of the glycosphingolipids which is the main composed of the cell membrane, beta-3-N-acetylglucosaminyltransferase 4 (B3GNT4) and UDP-glucose ceramide glucosyltransferase (UGCG) increase expression, HEXB and GLB1 reduced expression. The alteration of the coding genes of glycan structure biosynthesis and degradation pathways were significantly and characteristically in pathopoiesis mechanism of RRP. This abnormality may be the beginning of tumor form HPV infection. Show less

Anthocyanins belong to a large and widespread group of water-soluble phytochemicals and exhibit potent antioxidative and anti-inflammatory properties; however, the molecular mechanisms of these biochemical actions mediated by anthocyanins remain unclear. In this study, our data show that pretreatment of THP-1 macrophages with Cyanidin-3-O-beta-glucoside (C3G) for 12 h can enhance the expression and transcriptional activities of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) and liver X receptor alpha (LXRalpha). Furthermore, pretreatment of these cells with C3G for 12 h causes dose-dependent inhibition of lipopolysaccharide (LPS)-induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels together with a decrease in nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production. Consequently, addition of geranylgeranyl pyrophosphate ammonium salt (GGPP), an LXRalpha antagonist, significantly downregulates the inhibitory effect of C3G on LPS-induced iNOS and COX-2 expression in THP-1 macrophages, whereas the PPARgamma antagonist GW9662 has no effect. Further investigation revealed that LXRalpha might interfere with LPS-induced iNOS and COX-2 expression by suppressing the functional activation of nuclear factor-kappaB (NF-kappaB), not - as was previously proposed - by reducing NF-kappaB nuclear translocation. Taken together, these results indicate that LXRalpha activation has an essential role in the anti-inflammatory property of C3G. Moreover, they provide new insight into the molecular basis for the anti-inflammatory property of anthocyanins. Show less

To explore the relationship between the expression characteristics of lipid metabolism-related genes in the liver and early atherosclerotic lesions in apolipoprotein E and low density lipoprotein receptor gene double knockout (apoE(-/-)/LDLR(-/-)) mice. RT-PCR was used to detect the differential expression of lipid metabolism-related genes in the liver of apoE(-/-)/LDLR(-/-) and wild type (WT) mice. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) level as well as aortic morphology were also analyzed. Among the 11 lipid metabolism-related genes, apolipoprotein B100 (apoB100) mRNA levels were significantly higher in apoE(-/-)/LDLR(-/-)mice compared with WT mice. At 14 days, 1, 2 and 3 months of age, the level of mRNA expression were 1.55, 1.47, 1.50 and 2.42 folds of those of the age matched WT mice respectively. The fatty acid transporter (FAT/CD36) mRNA expression levels were higher in 14-day and 3-month old mice at 1.30 and 1.35 folds of those of the age matched WT mice, respectively. Apolipoprotein A IV (apoA IV) and Apolipoprotein AV (apoAV) mRNA levels were significantly down-regulated (0.89 fold decrease in 14-day, and 0.90 folds decrease in 3-month, respectively). The mRNA expression levels of apolipoprotein AI (apo AI), apolipoprotein F (apo F), peroxidase proliferator-activated receptor alpha (PPAR-alpha), liver X receptor alpha (LXRalpha), angiopoietin-like protein 3 (ANGPTL3), acyl-coenzymeA oxidase 1 (ACOX1) and carnitine palmitoyl transferase 1 (CPT1) had no significant changes. Serum TC, TG and LDL-C were higher than those of age matched WT mice at 7, 2 and 30 folds, respectively. Furthermore, apoE(-/-)/LDLR(-/-) mice demonstrated typical early atherosclerotic lesions at sinus and root regions of aorta in an age dependent manner. Alterations of the expression of lipid metabolism-related genes in liver play important roles in the development of AS in the apoE(-/-)/LDLR(-/-) mice at early ages. Show less

Bardet-Biedl syndrome (BBS) is a heterogeneous multisystemic disorder characterized primarily by five cardinal features of retinal degeneration, obesity, polydactyly, hypogenitalism and mental retardation. To date, six distinct BBS loci that have been identified on different chromosomes. BBS4 gene is mapped to 15q22.2-23, which when mutated can cause BBS4. Its protein shows strong homology to O-linked N-acetylglucosamine (O-GlcNAc) transferase. Here we report a splice variant of BBS4, which is 2556 bp in length and has an open reading frame coding a predicted 527 amino-acids protein. RT-PCR shows that the cDNA is widely expressed while it has higher expression levels in pancreas, liver and prostate. Show less

A polysaccharide from the water extract of cultured Cordyceps militaris was isolated through ethanol precipitation, deproteination and gel-filtration chromatography. Their molecular weight was determined using gel-filtration chromatography. The structure of polysaccharide CPS-1 was elucidated by sugar analysis, Smith degradation, IR and 13C-NMR spectroscopy. CPS-1 was shown to possess a significant antiinflammatory activity and suppressed the humoral immunity in mice but had no significant effects on the cellular immunity and the non-specific immunity. Show less

Axin is a recently identified tumor suppressor that plays an important role in liver and colon cancers. To gain further insights into the structure and function of Axin in controlling cell growth, we analyzed 54 colorectal cancer tissues for mutations in AXIN1 gene. We employed PCR amplification with 23 sets of primers against introns that encompassed the whole coding region of AXIN1 followed by single-strand conformation polymorphism (SSCP) analysis. After subcloning and sequencing analysis of the reamplified DNA from the aberrant bands, we found, in addition to 3 silent mutations, 6 missense point mutations in different functionally important regions. The missense mutation rate is hence 11%, suggesting that Axin deficiency may contribute to the onset of colorectal tumorigenesis. Show less

Carbamyl phosphate synthetase I (CPS1) is an initial enzyme of urea synthetase system. It exists exclusively in liver cells and epithelial cells of the small intestine. By immunocytochemistry, 70.5% of 88 surgically resected gastric carcinomas (42 advanced and 46 early gastric carcinomas) was found to be CPS1 immunoreaction positive, whereas all other carcinomas (of the esophagus, colon, pancreas, lung, breast, ovary, kidney, prostate and urinary bladder) tested were negative. CPS1 expression in gastric carcinoma was closely related to the types of mucin secreted by the carcinoma cells. Most carcinomas secreting sialomucin were CPS1 positive, yet those secreting sulfomucin or neutral mucin did not express CPS1. The types of intestinal metaplasia adjacent to the carcinoma correlated neither with CPS1 expression nor with the histological types of carcinoma. Owing to the fact that gastric carcinomas with CPS1 expression possess the characteristics of small intestinal epithelium, it is very likely that CPS1 can be used as a novel marker for gastric carcinoma originating from complete type intestinal metaplasia. Show less