Latest Update: 2014-04-07 13:16:21

細胞生化學實驗室 Laboratory of Cellular Biochemistry

研究領域 | Research Background

Notch signaling system—This ongoing work focuses on resolving the activated Notch complex and elucidating the molecular mechanism(s) of Notch signaling pathway in cell-fate determination and tumorgenesis. Receptor biology--This work focused on the structure-function relationship of G-protein coupled receptors. PCR methodology was employed to construct the chimeric or mutated receptors and various stable cell lines expressing wild type or mutated receptors were obtained. In addition, the ligand-receptor interaction, second messengers (IP3, cAMP, arachidonate) production, and Ca2+ signaling were measured. We also studied the functional regulation, which included desensitization, internalization, down-regulation and recycling, of the wild type and mutated receptors. In order to do immunocytochemical studies, the epitope-tag receptors were also constructed. Signal transduction—Depending on the cell culture conditions, the Gq-protein coupled receptors can induce both growth stimulating and growth inhibitory effects. The recombinant adenovirus expressing dominant negative mutants were used to elucidate the pathway of signal transduction of the Gq-protein coupled receptors both in pancreatic cell lines and primary pancreatic acini cells. Bacterial and bacteriophage genetics—1) These studies utilized the approaches of molecular biology to study the expression and regulation of bacteriophage T4 ribonucleotide reductase, the T4-encoded nrdA and nrdB, genes. Both nrdA and nrdB genes were also cloned into a single expression vector to overproduce the functionally active ribonucleotide reductase and to investigate the role of this enzyme in the deoxyribonucleoside triphosphate synthetase multienzyme complex. 2) My laboratory also isolated and characterized xylanases from Bacillus firmus. We have cloned two alkaliphilic thermostable xylanase genes and characterized their chemo-physical properties and in the process of studying their regulation. Bioorganic chemistry--Chemical and enzymatic methods were used to synthesize oligopeptides and bioactive peptides. Several of biosynthetic enzymes were cloned by PCR from the genome of various bacteria and over-expressed them in E. coli or Bacillus sp. These enzymes were used to synthesize therapeutically agents.

調節幹原細胞及前驅細胞發育的因子:Notch傳導系統及細胞命運發育過程中,前驅細胞常接受環境的信息而演化成合宜的細胞系列。Notch是這些信息之一,Notch是穿過細胞膜的受體,在各式各樣的發育過程調控細胞的命運。Notch蛋白的功能既是細胞表面的受體也是基因轉錄的直接調控者。一般Notch訊息活化後,會抑制影響細胞系列的基因的轉錄,進而抑制細胞的分化,如此可調節細胞的命運。當Notch ligand與Notch受體蛋白的細胞外部分結合反應後,會促使全長的Notch受體蛋白被蛋白質分解脢在細胞內被切斷,而細胞內的部分,所謂活化型 Notch(NICD), 會轉移到細胞核內與DNA結合蛋白CBF1作用,來活化調控細胞分化的基因的轉錄。有許多調控蛋白可以和NICD-CBF1的複合體結合來促進或壓制這複合體的功能。另外Notch的訊息傳導也可經由不需CBF1調控蛋白的其他過程。Notch訊息傳導的分子機制是現在很熱門的研究話題。為了尋找影響Notch訊息傳導途徑之新調節因子並研究其作用機制,本實驗室已建立一個良好的實驗分析系統。我們正使用各樣的分子生物和蛋白體的技術來我們正使用各樣的分子生物和蛋白體的技術來尋找新調節因子。另外活化型Notch(NICD)對細胞的生理作用,尤其幹原細胞,也是本實驗室的重點。