问答题
You have constructed a plasmid set containing a series of nucleotide insertions spaced along the length of the glucocorticoid(糖皮质激素)receptor gene. Each insertion encodes three amino acids. The map positions of the various insertions in the coding sequence of the receptor gene is as follows. The plasmids containing the receptor gene can be functionally expressed in COS cells(猴肾细胞)，which contain a steroid(类固醇)-responsive gene.
Using these cells, you determine the effect of each of these insertions in the receptor on the induction of steroid-responsive gene and on binding of the synthetic steroid dexamethasone(地塞米松)．The results of these analyses are summarized in the table.
请回答如下问题(用中文回答)：
(1)How many different functional domains does the glucocorticoid(糖皮质激素)receptor have? Indicate the position of these domains relative to the insertion map.
(2)Which domain of receptor is the steroid-binding domain?
(3)List two methods to determine which domain is the DNA binding domain.
Using these cells, you determine the effect of each of these insertions in the receptor on the induction of steroid-responsive gene and on binding of the synthetic steroid dexamethasone(地塞米松)．The results of these analyses are summarized in the table.
请回答如下问题(用中文回答)：
(1)How many different functional domains does the glucocorticoid(糖皮质激素)receptor have? Indicate the position of these domains relative to the insertion map.
(2)Which domain of receptor is the steroid-binding domain?
(3)List two methods to determine which domain is the DNA binding domain.
【正确答案】(1)该基因序列上有两种结构域，即DNA结合结构域(DNA binding domain)和类固醇结合结构域(steroid binding domain)。
表中所给Q、R、S三处插入碱基后，地塞米松(Dexamethasone)结合被强烈抑制，而其他位点插入突变后地塞米松结合不受影响，可知Q-R-S三处附近区域为类固醇结合结构域(steroid binding domain)。
而下游基因诱导情况(Induction)表格中，数据下调对应的插入位点有D、E、F、I、K、L、M、N、Q、R、S，可认为DNA结合结构域有三个，D-E-F，K-L-M-N，Q、R、S。
(2)如前(1)所分析，Q-R-S插入位点所包括的区域内即为类固醇结合结构域(steroid binding domain)。结构域准确定位还需进一步实验验证。
(3)由(1)中所分析，有三处区域有可能是DNA结合结构域，进一步的验证方法包括DNase footprinting足迹试验，或利用碱基缺失方法删除疑似区域，探究诱导作用的变化。
表中所给Q、R、S三处插入碱基后，地塞米松(Dexamethasone)结合被强烈抑制，而其他位点插入突变后地塞米松结合不受影响，可知Q-R-S三处附近区域为类固醇结合结构域(steroid binding domain)。
而下游基因诱导情况(Induction)表格中，数据下调对应的插入位点有D、E、F、I、K、L、M、N、Q、R、S，可认为DNA结合结构域有三个，D-E-F，K-L-M-N，Q、R、S。
(2)如前(1)所分析，Q-R-S插入位点所包括的区域内即为类固醇结合结构域(steroid binding domain)。结构域准确定位还需进一步实验验证。
(3)由(1)中所分析，有三处区域有可能是DNA结合结构域，进一步的验证方法包括DNase footprinting足迹试验，或利用碱基缺失方法删除疑似区域，探究诱导作用的变化。
【答案解析】