DYSFUNCTIONAL GROWTH-HORMONE RECEPTOR IN A STRAIN OF SEX-LINKED DWARF CHICKEN - EVIDENCE FOR A MUTATION IN THE INTRACELLULAR DOMAIN
DYSFUNCTIONAL GROWTH-HORMONE RECEPTOR IN A STRAIN OF SEX-LINKED DWARF CHICKEN - EVIDENCE FOR A MUTATION IN THE INTRACELLULAR DOMAIN
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DOI：
10.1677/joe.0.1420427
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发表时间：
1994-09-01
影响因子：
4
通讯作者：
BURNSIDE, J
中科院分区：
文献类型：
--
作者：
AGARWAL, SK;COGBURN, LA;BURNSIDE, J
性连锁侏儒鸡 (dwdw) 是研究 GH 不敏感性和 GH 受体 (GHR) 基因突变后果的有价值的动物模型。我们最近报道了从 Arbor Acre Farms, Inc.（美国康涅狄格州格拉斯顿伯里）获得的 dwdw 鸡品系中检测不到的肝脏 GH 结合活性和大小异常的转录本。鸡 GHR (cGHR) 基因的 Southern 印迹分析揭示了该 dwdw 鸡基因组 DNA 的 HindIII 和 EcoRI 消化物中存在限制性片段长度多态性。为了定位分子突变，我们分析了基因结构并确定了正常cGHR的3'非翻译区（3'UTR）的完整序列。利用这些信息，我们在康涅狄格州 (CT) dwdw 鸡品系的 cGHR 基因 3' 端发现了一个大的缺失。该缺失（1773 bp）包含编码区 3' 端的 27 个高度保守的氨基酸、框内终止密码子、通常在终止密码子下游 445 bp 处发现的不太常用的 Poly(A) 信号，以及 3' UTR 的大部分。由于这一缺失，27 个新氨基酸被取代，开放阅读框在到达转录终止位点之前又延伸了 26 个氨基酸。 dwdw cGHR 的新型羧基末端的预测氨基酸序列主要是疏水性的，具有多聚赖氨酸尾部，而野生型 (DwDw) cGHR 的羧基末端由亲水氨基酸组成。使用针对 cGHR 胞外结构域的抗血清进行蛋白质印迹分析，证实突变转录物已被翻译。这些观察结果表明，细胞内结构域的突变导致 cGHR 表达功能失调，这可以解释 CT dwdw 鸡的表型。
The sex-linked dwarf (dwdw) chicken represents a valuable animal model for studying GH insensitivity and the consequence of mutations in the GH receptor (GHR) gene. We have recently reported undetectable hepatic GH-binding activity and an aberrantly sized transcript in a strain of dwdw chickens obtained from Arbor Acre Farms, Inc. (Glastonbury, CT, USA). Southern blot analysis of the chicken GHR (cGHR) gene revealed a restriction-fragment length polymorphism in HindIII and EcoRI digests of genomic DNA in this strain of dwdw chicken. In order to localize the molecular mutation, we analysed the gene structure and determined the complete sequence of the 3' untranslated region (3' UTR) of the normal cGHR. With the use of this information, we located a large deletion in the 3' end of the cGHR gene of the Connecticut (CT) strain of dwdw chicken. This deletion (1773 bp) contained 27 highly conserved amino acids of the 3' end of the coding region, the in-frame stop codon, a less frequently used poly(A) signal that is normally found 445 bp downstream of the stop codon, and a large portion of the 3' UTR. Because of this deletion, 27 novel amino acids were substituted and the open reading frame was extended for an additional 26 amino acids before reaching the transcriptional termination site. The predicted amino acid sequence of the novel carboxyl-terminus of the dwdw cGHR is largely hydrophobic with a polylysine tail, whereas the carboxyl-terminus of the wild-type (DwDw) cGHR is composed of hydrophilic amino acids. Western blot analysis using antisera directed against the extracellular domain of the cGHR confirmed that the mutant transcript was translated. These observations suggested that the mutation in the intracellular domain results in expression of a dysfunctional cGHR which could account for the phenotype of the CT dwdw chicken.