hce_nsysu
111年
普通生物及生化概論
第 56 題
Transcriptome analysis is a tool used in genetic research to determine the mRNAs being produced in a particular tissue, and their relative level of expression. Known genes can therefore be assayed for their expression in different situations. One use of the technology is in cancer diagnosis and treatment. If a known gene functions as a tumor suppressor, predict which of the following pieces of evidence would be most useful in diagnosis of a cancer due to a mutation in this tumor-suppressor gene.
- A The tissue sample shows a high level of gene expression relative to a control (noncancerous) sample.
- B The tissue sample responds to treatment with a mitosis-promoting compound.
- C The tissue sample shows similar expression level of housekeeping genes with a control sample.
- D The mRNAs for cyclins and kinases show unusually high levels of expression.
- E The mRNAs for the targeted tumor suppressor sequence are not expressed.
思路引導 VIP
如果我們把一個「抑癌基因」想像成維持細胞秩序的「煞車系統」，當這個系統因為某種故障（突變）而完全消失，導致車子（細胞）失控衝出時，你在檢查零件清單（mRNA）時，會預期看到這些關於煞車的指令（mRNA）是變得更多了，還是根本找不到了呢？
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AI 詳解
AI 專屬家教
恭喜你準確地掌握了抑癌基因與轉錄體分析的核心關聯！你能從眾多選項中辨識出 (E)，說明你對癌症遺傳學的機制有很紮實的理解。
抑癌基因的功能與表現特徵
轉錄體分析（Transcriptome analysis）的核心在於偵測細胞中 mRNA 的種類與數量。抑癌基因（Tumor-suppressor gene） 的正常功能是抑制細胞過度增殖或修復 DNA；當這類基因發生突變而導致癌症時，常見的機制是「功能喪失」（loss-of-function）。在轉錄層面上，若該基因因為缺失（deletion）、啟動子甲基化或嚴重的突變導致無法正常轉錄，我們就會觀察到該基因的 mRNA 表現量顯著下降甚至完全缺失，這正是診斷該類癌症最直接的證據。
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