Identification of a human hepatocellular carcinoma-associated tumor suppressor gene by differential display polymerase chain reaction

Antisense overexpression of BMAL2 enhances cell proliferation

To identify genes that are frequently downregulated in hepatocellular carcinoma (HCC), a panel of putative underexpressed genes was first established by an in-house cDNA macroarray method. Two different assays, semiquantitative RT-PCR combined with Northern analysis and customized cDNA microarray analysis, were used to screen through these genes and the results were compared. Several genes, some with unknown function, were confirmed to be downregulated by both the methods. The effect of a downregulated gene, BMAL2, on cell proliferation was examined. Overexpression of antisense BMAL2 RNA in 293EBNA cells resulted in reduced cell cycle time, increased plating efficiency in soft agar, diminished TNF-alpha-induced increment of CPP32/caspase-3 activity, and a reduced proportion of cells in the G2 phase with a concomitantly increased proportion of cells in the S phase. In conclusion, by combining three different methods, we have obtained a panel of frequently down regulated genes in HCC, including BMAL2. Antisense overexpression of BMAL2 enhances cell proliferation.

Identification and validation of selective upregulation of ventricular myosin light chain type 2 mRNA in idiopathic dilated cardiomyopathy

BACKGROUND AND AIMS

the etiology of idiopathic dilated cardiomyopathy (IDCM) is unknown, methods such as suppression subtractive hybridization (SSH) and DNA microarray technology can help to identify genes which might be involved in the pathogenesis of this disease.

METHODS AND RESULTS

we used SSH which compared mRNA populations extracted from the left ventricular tissue of IDCM hearts and from the control tissue to identify sequences which correspond to genes up-regulated in IDCM. We identified ventricular myosin light chain type 2 (MLC2V), skeletal alpha-actin, long-chain-acyl-CoA-synthetase and mRNA for the protein KIAA0465 as differentially up-regulated genes. Expression of MLC2V mRNA was determined by RT-PCR in patients with end-stage heart failure caused by IDCM (n=11) or coronary artery disease (CAD, n=9) who underwent heart transplantation as well as the controls (n=6). MLC2V/GAPDH ratios were 2.95+/-0.32, 0.69+/-0.03 and 0.28+/-0.08 (arbitrary unit) for the IDCM group, the CAD group and controls, respectively (P<0.05). DNA microarray analysis confirmed the finding of MLC2V upregulation in IDCM (3.7- and 1.8-fold increase in MLC2V mRNA).

CONCLUSIONS

we have demonstrated that SSH is a useful method to identify differential myocardial upregulation of genes. Upregulation of MLC2V can be judged as a specific IDCM related feature, which might be clinically helpful.

In search of differentially expressed genes and proteins

A great challenge for modern cell biology is the successful examination of the co-expression of thousands of genes under physiological or pathological conditions and how the expression patterns define the different states of a single cell, tissue or a microorganism. Gene expression can be analyzed today on a large scale by advanced technical approaches for differential screening of proteins and mRNAs. The identification of differentially expressed mRNAs has been successfully applied to understand gene function and the underlying molecular mechanism(-s) of differentiation, development and disease state. Analysis of gene expression by the systematic mapping of thousands of proteins present in a cell or tissue can be achieved by the use of two-dimensional (2D) gel electrophoresis, quantitative computer image analysis, and protein identification techniques. In this article, we comment on some of these techniques and try to stress their advantages and drawbacks. We show how data from RNA/DNA mapping, sequence information from genome projects and protein pattern profiling can be linked with each other and annotated. These comprehensive approaches permit the study of differential gene and protein expressions in cells or tissues.