REGULATION OF RAT LUTEINIZING-HORMONE BETA-GENE EXPRESSION IN TRANSGENIC MICE BY STEROIDS AND A GONADOTROPIN-RELEASING-HORMONE ANTAGONIST
REGULATION OF RAT LUTEINIZING-HORMONE BETA-GENE EXPRESSION IN TRANSGENIC MICE BY STEROIDS AND A GONADOTROPIN-RELEASING-HORMONE ANTAGONIST
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DOI：
10.1095/biolreprod53.1.103
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发表时间：
1995-07-01
影响因子：
3.6
通讯作者：
SHUPNIK, MA
中科院分区：
文献类型：
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作者：
FALLEST, PC;TRADER, GL;SHUPNIK, MA
通过使用携带rLH β基因区域（从-2 kb到+41 bp）的转基因小鼠，研究了大鼠LH β (rLH β)基因的转录调控，该区域与荧光素酶（LUC）报告基因相连。7只创始小鼠均与B6SJLF1交配成功，均表现出LH β LUC转基因的种系传播。rLH β LUC活性水平在垂体中最高，但在卵巢、睾丸和下丘脑中也检测到活性。垂体rLH β LUC活性受性别、性腺切除术、性腺类固醇替代和GnRH拮抗剂施用的调节。女性垂体基底叶rLH β - LUC活性高于男性。这种活性在静脉曲张切除术后7天增加了2- 4倍，并且通过每日注射17 β -雌二醇将刺激活性抑制到完整水平(E(2)；300 ng)。在男性中，去势使垂体LUC活性增加了2- 4倍，并且通过每天注射25 μ g双氢睾酮（DHT）将其抑制到完整水平。性腺切除后，女性和男性垂体rLH β LUC活性的升高被每天注射GnRH拮抗剂Antide （60 μ g）阻断，该拮抗剂也以相似的程度抑制血清LH和LH β mRNA水平。在下丘脑测量的大鼠LH β LUC活性未被性腺切除术或性腺类固醇或安替德治疗改变，表明这种调节是垂体特异性的。这些结果表明，反馈调节垂体rLH β LUC基因的表达在该转基因小鼠模型中是可行的。rLH β基因在转录起始位点上游2kb的区域包含对GnRH产生转录应答的序列，这可能有助于在性腺切除术和性腺类固醇替代后LH β基因表达的变化。
Transcriptional regulation of the rat LH beta (rLH beta) gene was studied through the use of transgenic mice bearing a region of the rLH beta gene (from -2 kb to +41 bp) linked to a luciferase (LUC) reporter gene. All 7 founder mice were successfully bred with B6SJLF1 mates and exhibited germ line transmission of the LH beta LUC transgene. Levels of rLH beta LUC activity were highest in the pituitary, but activity was also detected in ovary, testis, and hypothalamus. Pituitary rLH beta LUC activity was found to be regulated by gender, gonadectomy, gonadal steroid replacement, and GnRH antagonist administration. Females had higher basal pituitary rLH beta LUC activity than males. This activity was increased 2- to 4-fold seven days postovariectomy, and stimulated activity was suppressed to intact levels by daily injections of 17 beta-estradiol (E(2); 300 ng). In males, castration increased pituitary LUC activity 2- to 4-fold, and this was suppressed to intact levels by daily injections of 25 mu g dihydrotestosterone (DHT), The postgonadectomy rise in pituitary rLH beta LUC activity in females and males was blocked by daily administration of the GnRH antagonist Antide (60 mu g), which also suppressed serum LH and LH beta mRNA levels to a similar extent. Rat LH beta LUC activity measured in the hypothalamus was not altered by gonadectomy or gonadal steroid or Antide treatment, demonstrating that this regulation is pituitary-specific. These results indicate that feedback regulation of pituitary rLH beta LUC gene expression is operational in this transgenic mouse model. The region of the rLH beta gene within 2 kb upstream from the transcriptional start site contains sequences that confer transcriptional responses to GnRH, which may contribute to the changes in LH beta gene expression after gonadectomy and after gonadal steroid replacement.