MELANOGENIC CORRELATES OF AGOUTI GENE EXPRESSION

AGOUTI 基因表达的黑色素生成相关性

• 批准号: 2082213
• 负责人: NELS H GRANHOLM
• 金额: $ 10.42万
• 依托单位: SOUTH DAKOTA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-10 至 2000-07-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2082213
• 关键词: biological signal transduction; diabetes mellitus genetics; fertility; gene expression; immunosuppression; laboratory mouse; lethal genes; melanins; melanocyte; melanoma; melanosomes; molecular pathology; monophenol monooxygenase; northern blottings; obesity; pigmentation disorders; western blottings

Our broad, long-term objective is to determine why mutations of the murine agouti locus like lethal yellow (Ay) and viable yellow (Avy) cause pathologies of the Lethal Yellow Syndrome (LYS)-obesity, aberrant pigmentation, cancer, enhanced growth, immunosuppression, infertility, and diabetes. The agouti locus regulates the type of pigment (black and/or yellow) synthesized within follicular melanocytes (Silvers, 19790. Agouti alleles alter specific melanogenic parameters (Ito, 1993; Tamate et al., 1989; Granholm et al., 1990b). With the advent of agouti gene isolation, cloning, sequencing, and partial characterization (Bultman et al., 1992; Miller et al., 1993), we now for the first time have an opportunity to correlate the molecular events of melanogenesis with virtually unequivocal evidence of agouti expression (i.e., presence of agouti transcripts followed by synthesis of agouti proteins). Specific Aims include: 1) Developmental Northern analyses together with specific assays of melanogenesis (tyrosinase (both tyrosine hydroxylase and dopa oxidase), type of melanin (total, eu-, and phaeomelanin), dopachrome tautomerse (DT), and melanosome differentiation via transmission electron microscopy) on regenerating and newborn hair bulbs of Strain C57BL\6J wild-type agouti(AwJ/AwJ), lethal yellow (Ay/a), and nonagouti black (a/a) genotypes and 2) Northern and Western analyses of extrafollicular "target tissues" of the lYS (fat stores-obesity, ovarian follicles-infertility, pituicytes- potential MSH lesions, and splenocytes-immunosuppression); we plan to determine the chronology of agouti expression and assess whether Ay-induced pathologies in these tissues arise autonomously or by systemic action of agouti proteins made elsewhere. With respect to human health, experiments designed to correlate agouti expression with precise components of melanogenesis will provide refined information on how the agouti locus, one of about 50 genetic loci involved in the regulation of pigmentation, determines the balance of black, yellow, or both pigments within follicular melanocytes. An understanding of the agouti-encoded regulation of this "pigment equilibrium" (i.e., switch from black-to-yellow-to-black) should be productive for the diagnosis and treatment of melanomas an other pigment cell disorders, because we will possess a more fundamental knowledge of pigment cell metabolism and therefore a greater potential for drug intervention. Studies on aberrant LYS "target tissues" of adult Ay/a mice may allow us to identify molecular lesions common to those same conditions in humans -obesity, cancer, abnormal growth, compromised immunity, infertility, and diabetes resulting potentially in the development of new therapies. Because agouti expression apparently depends upon a signaling mechanism, we may discover that the common lesion uniting many of the pathologies of the LYS is a fundamental defect in cell signaling. Elucidation of the molecular bases of an Av- induced signaling lesion may yield important data on similar signaling lesions in humans.

我们广泛、长期的目标是确定小鼠突变的原因 刺豚鼠基因座如致死黄 (Ay) 和活黄 (Avy) 原因 致命性黄色综合症 (LYS) 的病理学 - 肥胖、异常 色素沉着、癌症、促进生长、免疫抑制、不孕症和 糖尿病。 刺鼠基因座调节色素的类型（黑色和/或 黄色）在滤泡黑素细胞内合成（Silvers，19790。Agouti 等位基因改变特定的黑色素生成参数（Ito，1993；Tamate 等人， 1989； Granholm 等人，1990b)。 随着刺豚鼠基因分离技术的出现， 克隆、测序和部分表征（Bultman 等，1992； Miller 等人，1993），我们现在第一次有机会 将黑素生成的分子事件与几乎明确的 刺豚鼠表达的证据（即刺豚鼠转录本的存在 随后合成刺豚鼠蛋白）。 具体目标包括：1) 发育性 Northern 分析以及特定分析 黑色素生成（酪氨酸酶（酪氨酸羟化酶和多巴氧化酶）， 黑色素类型（总黑色素、欧盟黑色素和褐黑色素）、多巴色素互变异构体 (DT)、 和通过透射电子显微镜的黑素体分化） C57BL\6J野生型的再生和新生毛球 刺豚鼠 (AwJ/AwJ)、致死黄 (Ay/a) 和非刺豚鼠黑色 (a/a) 基因型 2) 滤泡外“目标组织”的 Northern 和 Western 分析 lYS（脂肪储存-肥胖、卵泡-不孕、垂体细胞- 潜在的 MSH 损伤和脾细胞免疫抑制）；我们计划 确定agouti表达的时间顺序并评估Ay是否诱导 这些组织中的病理是自主产生的或通过系统作用产生的 其他地方生产的刺豚鼠蛋白。 就人类健康而言，旨在将刺豚鼠关联起来的实验 表达黑色素生成的精确成分将提供精细的 有关agouti基因座（约50个基因位点之一）如何参与的信息 在色素沉着的调节中，决定黑色、黄色、 或滤泡黑素细胞内的两种色素。 的理解 这种“色素平衡”的agouti编码调节（即从 黑色到黄色到黑色）应该对于诊断和 治疗黑色素瘤和其他色素细胞疾病，因为我们将 拥有色素细胞代谢的更基础知识 因此药物干预的潜力更大。 异常研究 成年 Ay/a 小鼠的 LYS“靶组织”可能使我们能够识别分子 人类相同情况下常见的病变——肥胖、癌症、 生长异常、免疫力受损、不孕和糖尿病 可能有助于开发新疗法。 因为刺豚鼠表情 显然取决于信号机制，我们可能会发现 LYS 的许多病理学的共同病变是一个基本的 细胞信号传导缺陷。 阐明 Av- 的分子基础 诱导的信号传导损伤可能会产生类似信号传导的重要数据 人体的病变。