			Home About us Contact

Decreased Expression Levels (decreased + expression_level)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Short rare MUC6 minisatellites-5 alleles influence susceptibility to gastric carcinoma by regulating gene,

HUMAN MUTATION, Issue 8 2010
Jeong-Ah Kwon
Abstract The human MUC6 gene, which is reported to be expressed in the stomach and gall bladder, is clustered on chromosome 11p15.5 with other secreted mucins. In this study, the genomic structure of MUC6 has been analyzed and five VNTR (minisatellites; MS1,MS5) were identified. These minisatellites were analyzed in genomic DNA extracted from 1,103 controls, 470 gastric cancer patients, and multigenerational families. Five novel minisatellites were found to be polymorphic and transmitted through meiosis by Mendelian inheritance in families. We evaluated allelic variation in these minisatellites to determine if such variation affected the susceptibility to gastric cancer. A significant association (odds ratio [OR]=7.08) between short rare MUC6,MS5 alleles and relative risks were observed for gastric cancer (95% confidence interval [CI], 1.43,35.19; P=0.005). To investigate the function of minisatellite alleles of MUC6,MS5, we examined the effects on gene expression from luciferase reporters when inserted with minisatellites. Interestingly, when the shortest allele (7TR) was inserted in the promoter, the expression level decreased over 20-fold (P<0.001) in normal and cancer cell lines. Furthermore, the cancer-specific rare allele (TR8) also showed decreased expression levels in cancer cells. Therefore, we suggest that the short rare MUC6,MS5 alleles may be related to cancer development by the regulation of MUC6 expression. Hum Mutat 31:1,8, 2010. © 2010 Wiley-Liss, Inc. [source]

Cadmium modulates proliferation and differentiation of human neuroblasts

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2009
Massimo Gulisano
Abstract Cadmium is an environmental pollutant inducing numerous pathological effects, including neurological disorders and brain diseases. However, little is known about the molecular mechanisms of cadmium in affecting neurons and in inducing neurotoxicity in the development of the human brain. We have recently established, cloned, and propagated in vitro a primary long-term cell culture (FNC-B4) obtained from the human fetal olfactory neuroepithelium. In the present study, we show that different concentrations of cadmium chloride (CdCl2) induced dose-dependent biological effects in FNC-B4 cells. A low concentration (10 ,M) of CdCl2 stimulated neuroblast growth, whereas a high concentration (100 ,M) inhibited the growth and the viability of neuroblasts inducing morphological and cytoskeletal alterations as well as apoptotic cell death. We also observed that CdCl2 affected, in a dose-dependent manner, the differentiation of FNC-B4 neuroblasts, with increased mRNA and protein levels of differentiation markers and decreased expression levels of neuronal stem markers. Furthermore, differentiated cells co-expressed glial and neuronal markers. We suggest that CdCl2 in FNC-B4 neuroblasts might represent a selective cue by which, in a heterogeneous primary culture, the more differentiated mature cells die, whereas the undifferentiated cells, at the same time glial and neuronal progenitors, are forced to access a state of differentiation. © 2008 Wiley-Liss, Inc. [source]

Disturbance of circadian gene expression in hepatocellular carcinoma

MOLECULAR CARCINOGENESIS, Issue 12 2008
Yueh-Min Lin
Abstract Circadian rhythm plays an important role in the regulation of digestive system. The human circadian rhythm is controlled by at least nine circadian genes. The aims of this study are to understand the expression of the circadian genes between hepatocellular carcinoma tissues and nontumor tissues, and to explore the possible mechanism(s) contributing to the difference. We analyzed differential expression of the 9 circadian genes in 46 hepatocellular carcinoma and paired noncancerous tissues by real-time quantitative RT-PCR and immunohistochemical detection. We also tested the possible regulatory mechanism(s) by direct sequencing and methylation PCR analysis. Our results showed that decreased expression levels of PER1, PER2, PER3, CRY2, and TIM in hepatocellular carcinomas were observed. Decreased-expression of these genes was not caused by genetic mutations, but by several factors, such as promoter methylation, overexpression of EZH2 or other factors. The downexpression of more circadian genes may result in disturbance of cell cycle, and it is correlated with the tumor size. Downregulation of circadian genes results in disturbance of circadian rhythm in hepatocellular carcinoma which may disrupt the control of the central pacemaker and benefit selective survival of cancerous cells and promote carcinogenesis. © 2008 Wiley-Liss, Inc. [source]

OsNOA1/RIF1 is a functional homolog of AtNOA1/RIF1: implication for a highly conserved plant cGTPase essential for chloroplast function

NEW PHYTOLOGIST, Issue 1 2010
Hongjia Liu
Summary ,The bacterial protein YqeH is a circularly permuted GTPase with homologs encoded by plant nuclear genomes. The rice homolog OsNOA1/RIF1 is encoded by the single-copy gene Os02g01440. OsNOA1/RIF1 is expressed in different tissues and is light-inducible. The OsNOA1/RIF1-EYFP fusion protein was targeted to chloroplasts in transgenic Arabidopsis plants. In addition, the rice homolog was able to rescue most of the growth phenotypes in an Arabidopsis rif1 mutant. ,Rice (Oryza sativa) OsNOA1/RIF1 RNAi mutant seedlings were chlorotic with reduced pigment contents and lower photosystem II (PSII) efficiency. However, the expressions of the chloroplast-encoded genes rbcL, atpB, psaA and psbA were not affected. By contrast, reduced abundance of the chloroplast 16S rRNA was observed in the mutant. ,Quantitative iTRAQ-LC-MS/MS proteomics investigations revealed proteome changes in the rice mutant consistent with the expected functional role of OsNOA1/RIF1 in chloroplast translation. The RNAi mutant showed significantly decreased expression levels of chloroplast-encoded proteins as well as nuclear-encoded components of chloroplast enzyme complexes. Conversely, upregulation of some classes of nonchloroplastic proteins, such as glycolytic and phenylpropanoid pathway enzymes, was detected. ,Our work provides independent indications that a highly conserved nuclear-encoded cGTPase of likely prokaryotic origin is essential for proper chloroplast ribosome assembly and/or translation in plants. [source]