High expression of bovine α glutathione S-transferase (GSTA1, GSTA2) subunits is mainly associated with steroidogenically active cells and regulated by gonadotropins in bovine ovarian follicles
High expression of bovine α glutathione S-transferase (GSTA1, GSTA2) subunits is mainly associated with steroidogenically active cells and regulated by gonadotropins in bovine ovarian follicles
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DOI：
10.1210/en.140.8.3507
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发表时间：
1999-08-01
期刊：
影响因子：
4.8
通讯作者：
Lussier, JG
中科院分区：
文献类型：
--
作者：
Rabahi, F;Brûlé, S;Lussier, JG
我们以前已经表明，一个主要的28-30 kDa的蛋白质组减少后，在牛颗粒细胞（GC）的LH激增。在本研究中，我们已经确定了这组中的两种蛋白质，以寻找可能干预卵泡发生和卵母细胞成熟的因素。针对28 kDa或29 kDa牛GC蛋白的多克隆抗体用于筛选互补DNA（cDNA）表达文库。这导致了α类谷胱甘肽S-转移酶的两种同工酶亚基的表征，命名为bGSTA 1和bGSTA 2。bGSTA 1（25.4 kDa，pI 8.9; 791 bp cDNA; GenBank登录号BTU 49179）和bGSTA 2（25.6 kDa，pI 7.2; 959 bp cDNA; GenBank登录号AF 027386）均具有222个氨基酸。推导的氨基酸序列进行了比较，并显示82%（bGSTA 1）和74%（bGSTA 2）的同一性，人GSTA 1，而bGSTA 1和bGSTA 2是81%的相同性彼此。bGSTA 2代表了一种新的GSTA亚基，因为它含有在任何其他物种和GST类别中未发现的特定16个氨基酸序列。北方印迹显示bGSTA 1和bGSTA 2共表达并且具有组织特异性，分别具有1.2 kb和1.4 kb的bGSTA 1和bGSTA 2单转录物。在GC、黄体、肾上腺、睾丸、肝、肺、甲状腺、肾和子叶中均检测到mRNA，其相对丰度各不相同。bGSTA 1/bGSTA 2 mRNA的比率在组织之间变化，表明这些基因的表达受到不同的控制。免疫组化结果显示，GSTA的表达具有细胞特异性，与GC和卵泡膜细胞、小黄体细胞、间质细胞、肝细胞、肾上腺皮质、肾上腺髓质中的特定嗜铬细胞、肾近曲小管细胞和细支气管中的Clara细胞相关。体内研究表明，hCG处理前排卵前卵泡壁中bGSTA 1 mRNA水平升高，但在hCG处理后12 h下降了77%。然而，在FSH刺激的排卵前卵泡中，在hCG注射后24小时，两种GSTAs的mRNA仅下降21%。我们的结论是，bGSTA 1和bGSTA 2的表达是组织和细胞特异性的，与类固醇生成活性细胞，并在牛卵泡中的促性腺激素分泌调节。
We have previously shown that a major group of 28-30 kDa proteins decreases after the LH surge in bovine granulosa cells (GC). In the present study, we have characterized two proteins in this group in search of factors that may intervene in folliculogenesis and oocyte maturation. Polyclonal antibodies raised against 28 kDa or 29 kDa bovine GC proteins were used to screen a complementary DNA (cDNA) expression library. This resulted in the characterization of two isoenzyme subunits for alpha class glutathione S-transferase, named bGSTA1 and bGSTA2. Both bGSTA1 (25.4 kDa, pI 8.9; 791 bp cDNA; GenBank Accession No. BTU49179) and bGSTA2 (25.6 kDa, pI 7.2; 959 bp cDNA; GenBank Accession No. AF027386) have 222 amino acids. The deduced amino acid sequences were compared and showed 82% (bGSTA1) and 74% (bGSTA2) identity to human GSTA1, whereas bGSTA1 and bGSTA2 are 81% identical to each other. The bGSTA2 represents a novel GSTA subunit because it harbors a specific 16 amino acid sequence not found in any other species and GST classes. Northern blots showed that bGSTA1 and bGSTA2 are coexpressed and are tissue specific with single transcripts of 1.2 kb and 1.4 kb, respectively for bGSTA1 and bGSTA2. The messenger RNA (mRNA) were detected in GC, corpus luteum, adrenal gland, testis, liver, lung, thyroid, kidney and cotyledon, and the relative abundance of their mRNA varied. Ratios of bGSTA1/bGSTA2 mRNA vary between tisssues, indicating that expression of these genes is controlled differently. Immunohistochemistry observations revealed that expression of GSTA is cell specific, being associated with GC and theca cells, small luteal cells, Leydig cells, hepatocytes, adrenal cortex, specific chromaffin cells in the adrenal medulla, renal proximal convoluted tubular cells, and Clara cells in the bronchioles. Studies in vivo showed that levels of mRNA for bGSTA1 were elevated in folicular wall of preovulatory follicles before hCG treatment, but decreased by 77% 12 h after hCG injection. However, in FSH stimulated preovulatory follicles, the decrease in mRNA for both GSTAs was only 21% at 24 h following hCG injection. We concluded that bGSTA1 and bGSTA2 expression is tissue- and cell-specific, is associated with steroidogenically active cells, and is hormonally regulated by gonadotropins in the bovine ovarian follicle.