CRD-BP and β-TrCP in colorectal cancer / 国际肿瘤学杂志

Coding region instability determinant (CRD) is one of the influence factors of oncogene c-myc.Coding region instability determinant-binding protein (CRD-BP) can connect with CRD in order to protect CRD from nuclease attack,prevent rapid degradation of c-myc mRNA,and increase c-myc protein content.Beta-transducin repeats-containing protein (β-TrCP) can affect cell growth,differentiation,apoptosis and oncogenesis by regulating multiple signaling pathways and cell cycle.The overexpression of CRD-BP can upregulate the expression of β-TrCP and both of them play important roles in the tumorigenesis,progression,metastasis and invasion of colorectal cancer.

Gene expression profiling of light-induced retinal degeneration in phototransduction gene knockout mice

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.

Gene Expression Profiling of Breast Cancers with Emphasis of beta-Catenin Regulation

To gain molecular understanding of carcinogenesis of breast cancer, gene expression profiles were analyzed using cDNA microarray representing 4,600 cDNAs in 10 breast cancer samples and the adjacent noncancerous breast tissues from the same patients. The alterations in gene expression levels were confirmed by reversetranscription PCR in four randomly selected genes. Genes that were differently expressed in cancer and noncancerous tissues were identified. 106 (of which 55 were known) and 49 (of which 28 were known) genes were up- or down-regulated, respectively, in greater than 60% of the breast cancer samples. In cancer tissues, genes related to cell cycle, transcription, metabolism, cell structure/motility and signal transduction were mostly up-regulated. Furthermore, three cancer tissues showing immunohistochemically aberrant accumulation of beta-catenin in the nucleus and/or cytoplasm revealed down-regulation of Siah and Axin genes and up-regulation of Wnt and c-myc genes. These findings were highly consistent with Wnt signaling pathway associated with beta-catenin regulation previously suggested by others. Our studies, therefore, provide not only a molecular basis to understand biological processes of breast cancer but also useful resources to define the mechanism of beta-catenin expression in tumorigenesis of breast cancer.

IN SITU HYBRIDIZATION DETECTION OF GUSTDUCIN AND TRANSDUCIN EXPRESSION IN TASTE BUDS / 解剖学报

Objective The in situ hybridization method was used with signal amplification system for detecting G-protein expression in taste buds. Methods The gene of gustducin and ?- rod transducin in rat are cloned by RT- PCR. Their sense and antisense probes were labeled with digoxigenin. About 150 taste buds in rat vallate and foliate papillae were analyzed. Results The results showed that there were 1.2 transducin-positive cells and 6.2 gustducin-positive cells counted in each taste bud profile on average. The number of gustduin-positive cells was approximately five times more than transducin-positive cells in taste buds. There were 4. 1% gustducin-positive cells and 0.8% transducin-positive cells in all taste cells. It could not be seen any cross reation of transducin probe to gustducin target. The high expression of transducin in retina was also observed but no gustducin expression could be detected. Conclusion The result of present study proved that both transducin and gustducin were taste G-protein and gustducin was high expressed. Both of them might be involved in taste signal transduction.