Conversion of bovine growth hormone cysteine residues to serine affects secretion by cultured cells and growth rates in transgenic mice.
Conversion of bovine growth hormone cysteine residues to serine affects secretion by cultured cells and growth rates in transgenic mice.
复制标题
牛生长激素半胱氨酸残基向丝氨酸的转化影响培养细胞的分泌和转基因小鼠的生长速率。
作者：
X. Chen;A. Shafer;J. Yun;Y. Li;T. Wagner;J. Kopchick
GH具有两个二硫键。我们着手确定牛（B）GH的二硫键相对于体外培养细胞分泌激素和促进转基因小鼠生长的能力的重要性。我们已经产生了六个突变的bGH基因编码丝氨酸（Ser）取代半胱氨酸（Cys）。这些突变的基因用于产生bGH类似物，其中一个或两个二硫键被破坏。当bGH的小环被破坏（Cys 181-Ser或Cys 189-Ser）时，发现小鼠L细胞分泌的bGH类似物的水平与野生型bGH相当。然而，当大环被消除（Cys 53-Ser或Cys 164-Ser）时，分泌急剧减少。这些bGH类似物的免疫荧光研究揭示了两种不同的亚细胞定位模式。牛生长激素类似物与突变的小环表现出类似于野生型bGH的核周分布，但类似物含有一个破坏的大环揭示了一个统一的细胞质分布模式。当这些突变的bGH基因被单独引入转基因小鼠，只有那些动物表达bGH类似物与大环完整表现出生长增强的表型。表达缺乏大环的bGH类似物的转基因小鼠显示出与非转基因小鼠相似的生长速率。这些结果表明，大环的完整性，而不是小环，是必不可少的生长促进活性的bGH在转基因小鼠。
GHs have been found to possess two disulfide bonds. We set out to determine the importance of bovine (b) GH's disulfide bonds relative to the ability of the hormone to be secreted by cultured cells in vitro and to promote growth in transgenic mice. We have generated six mutated bGH genes that encode serine (Ser) substitutions for cysteines (Cys). These mutated genes were used to generate bGH analogs in which either one or both disulfide bonds are destroyed. When the small loop of bGH was destroyed (Cys181-Ser or Cys189-Ser), the bGH analogs were found to be secreted by mouse L-cells at levels comparable to those of wild-type bGH. However, secretion was drastically reduced when the large loop was abolished (Cys53-Ser or Cys164-Ser). An immunofluorescence study of these bGH analogs revealed two distinct patterns of subcellular localization. Bovine GH analogs with mutations in the small loop demonstrated a perinuclear distribution similar to that of wild-type bGH, but analogs containing a disrupted large loop revealed a uniform cytoplasmic distribution pattern. When these mutated bGH genes were individually introduced into transgenic mice, only those animals that expressed bGH analogs with the large loop intact demonstrated a growth-enhanced phenotype. Transgenic mice that expressed bGH analogs lacking the large loop showed growth rates similar to those of nontransgenic mice. These results suggest that the integrity of the large loop, but not that of the small loop, is essential for the growth-enhancing activity of bGH in transgenic mice.
DOI：
10.1016/s0021-9258(19)39231-2
发表时间：
1990-04
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Robert;-W.;DomsIlII;John;-K.;Rose
通讯作者：
Robert;-W.;DomsIlII;John;-K.;Rose
质粒中的快速定点诱变。
影响因子：
3.5
作者：
Foss,K;McClain,WH
通讯作者：
McClain,WH
转基因小鼠中嵌合磷酸烯醇丙酮酸羧激酶/牛生长激素基因的组织特异性表达和饮食调节。
DOI：
--
发表时间：
1988
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
McGrane,MM;deVente,J;Yun,J;Bloom,J;Park,E;Wynshaw-Boris,A;Wagner,T;Rottman,FM;Hanson,RW
通讯作者：
Hanson,RW