GENETIC-VARIATION OF THE GLUCOCORTICOID RECEPTOR FROM A STEROID-RESISTANT PRIMATE
GENETIC-VARIATION OF THE GLUCOCORTICOID RECEPTOR FROM A STEROID-RESISTANT PRIMATE
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DOI：
10.1677/jme.0.0070089
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发表时间：
1991-10-01
影响因子：
3.5
通讯作者：
LORIAUX, DL
中科院分区：
文献类型：
--
作者：
BRANDON, DD;MARKWICK, AJ;LORIAUX, DL
新热带棉顶绒猴（Saguinus oedipus）是一种新大陆灵长类动物，与包括人类在内的旧大陆灵长类动物相比，其血浆皮质醇总浓度和游离浓度显著升高。在各种新大陆灵长类动物中发现的终末器官对糖皮质激素的相对“抵抗”归因于糖皮质激素受体（GR）对糖皮质激素的亲和力降低。它已被证明，绒猴GR与地塞米松的结合亲和力约低10倍，与人类GR相比。我们已经研究了绒猴GR的GR功能结构域的分子克隆和测序的一级结构。利用来自绒猴来源的淋巴细胞系的poly（A）+ RNA在噬菌体载体pMDA-gt 10中构建cDNA克隆文库，并利用人GR cDNA进行筛选。DNA测序确定了76个单独的核苷酸取代的绒猴GR的编码区。绒猴GR的核苷酸序列与人类GR cDNA编码区的比较表明，约97%的整体序列同源性。30个核苷酸的取代导致在预测的绒猴GR的氨基酸序列（28个氨基酸的取代）的改变。从778个氨基酸的预测绒猴GR的大小是约90 000，这是与以前的大小估计的人和绒猴GR的协议。在绒猴GR的氨基酸序列的变化是最大的对氨基末端，包括tau-1结构域的pupregion参与转录激活。DNA结合结构域含有一个额外的密码子（精氨酸）。绒猴GR的DNA结合域与类固醇受体超家族的其他成员的比较表明，额外的精氨酸发生在与人类雄激素受体和erb-A原癌基因的interfinger区域内的其他氨基酸插入相同的位置。在类固醇结合结构域内只有四个错义取代。这些取代中的两个发生在与GR与90 kDa热休克蛋白结合相关的转导位点内。这些数据表明，减少GR亲和力的绒猴糖皮质激素可能是由于一个或多个功能域的GR基因的一级结构的改变。此外，其他重要的调节功能，如转录激活，DNA结合和受体转导，也可能受到影响。
The neotropical cotton-top marmoset (Saguinus oedipus) is a New World primate known to have markedly increased total and free plasma cortisol concentrations when compared with Old World primates including man. The relative end-organ 'resistance' to glucocorticoids found in various New World primates has been attributed to a glucocorticoid receptor (GR) with diminished affinity for glucocorticoids. It has been demonstrated that the marmoset GR has approximately tenfold lower binding affinity for dexamethasone when compared with the human GR. We have examined the primary structure of the marmoset GR by molecular cloning and sequencing of GR functional domains. A library of cDNA clones was constructed in the phage vector lambda-gt10 using poly(A)+ RNA from a marmoset-derived lymphoid cell line, and screened using the human GR cDNA. DNA sequencing determined 76 individual nucleotide substitutions in the coding region of the marmoset GR. Comparison of the marmoset GR nucleotide sequence with the human GR cDNA coding region indicated an overall sequence homology of about 97%. Thirty of the nucleotide substitutions lead to alterations in the predicted amino acid sequence (28 amino acid substitutions) of the marmoset GR.The size of the marmoset GR predicted from the 778 amino acids is approximately 90 000 which is in agreement with previous size estimates of the human and marmoset GRs. Alterations of amino acid sequence in the marmoset GR were greatest towards the amino terminus, including the tau-1 domain putatively involved in transcriptional activation. The DNA-binding domain contained an additional codon (arginine). Comparison of the DNA-binding domain of the marmoset GR with other members of the steroid receptor superfamily indicates that the additional arginine occurs in the same position as other amino acid insertions within the interfinger region of the human androgen receptor and the erb-A proto-oncogene. There are only four missense substitutions within the steroid-binding domain. Two of these substitutions occur within the transducing site which has been associated with binding of the GR to a 90 kDa heat shock protein. These data suggest that diminished GR affinity for glucocorticoids in the marmoset may be due to alterations in the primary structure of one or more functional domains of the GR gene. In addition, other important regulatory functions, such as transcriptional activation, DNA binding and receptor transduction, may also be affected.