Regulation of mammary gland biology by RLIM/Rnf12 and the paternal X chromosome

RLIM/Rnf12 和父本 X 染色体对乳腺生物学的调节

• 批准号: 8439608
• 负责人: INGOLF M BACH
• 金额: $ 33.49万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8439608
• 关键词: Adult; Alleles; Alveolar; Alveolar Cell; Apoptosis; Biology; Cell Death; Cell Death Signaling Process; Cell Nucleus; Cell Survival; Cells; Cessation of life; Clonal Expansion; Cytoplasmic Protein; Development; Disease; Dosage Compensation (Genetics); Embryo; Ensure; Enzymes; Epigenetic Process; Epithelial Cells; Evolution; Female; Fingers; Genes; Genetic; Goals; Hour; Inner Cell Mass; Knock-in Mouse; Knock-out; Knockout Mice; Laboratories; LacZ Genes; Lactation; Link; Mammary gland; Mediating; Milk; Molecular; Morphogenesis; Mus; Nuclear; Oocytes; Parents; Pathway interactions; Pattern; Phosphorylation; Placenta; Pregnancy; Probability; Process; Production; Proteins; Puberty; Regulation; Reporter Genes; Research; Role; Somatic Cell; System; Testing; Tissues; Transgenic Mice; Ubiquitin; Weaning; Work; X Chromosome; X Inactivation; alveolar epithelium; cell motility; cofactor; genetic analysis; imprint; in vivo; mammary epithelium; mouse model; multicatalytic endopeptidase complex; mutant; novel; precursor cell; pregnant; public health relevance; recombinase; sex; transcription factor; transmission process; trophoblast; ubiquitin ligase

DESCRIPTION (provided by applicant): To ensure appropriate dosage compensation, female cells selectively inactivate one of their two X chromosomes in a process called X chromosome inactivation (XCI), a form of epigenetic regulation. In early female mouse embryos, somatic cells of the inner cell mass inactivate their paternal or maternal X chromosomes with equal probability. Thus, cells in somatic female tissues display a random XCI pattern. The mammary gland represents a prime object to investigate genetic pathways that control the specification, proliferation, differentiation, survival and death of cells. Cellular survival and cell death decisons are critically regulated by the ubiquitin proteasome system (UPS). In particular, RING finger ubiquitin ligases act as key components in cell death signaling cascades. The functions of these enzymes for cell survival/death often rely on their RING finger-dependent ubiquitin ligase activity as well as their cellular localizations. We have generated a conditional KO mouse model for the RING finger ubiquitin ligase RLIM which is encoded by the X-linked gene Rnf12. Our preliminary results indicate that knockout (KO) of Rnf12 in female mammary glands inhibits alveolar differentiation and milk production upon pregnancy. We find that alveolar cells lacking RLIM undergo apoptosis as they differentiate from mammary epithelia. Our results suggest further that these functions are mediated primarily by the paternal Rnf12 allele due to nonrandom XCI in mammary epithelial cells which primarily silence their maternal X chromosomes. We hypothesize 1) that RLIM is crucially involved in alveolar cell survival pathways and is key for triggering involution, and 2) sex-specific epigenetic regulation of mammary gland biology by the paternal X chromosome. The proposed project will test these hypotheses and identify underlying molecular mechanisms in three specific aims. Aim 1 will establish RLIM as triggering weaning-induced alveolar cell death/involution and test the involvement of the UPS system. Aim 2 will connect RLIMs survival functions with nucleo- cytoplasmic shuttling, while Aim 3 establishes and examines mechanisms to establish the non-random XCI pattern in mammary precursor cells. Combined our results will establish RLIM as a novel paradigm in regulating alveolar cell survival/death pathways. Moreover, the results of our research will show that mammary gland biology is decisively controlled by sex-specific epigenetic mechanisms with profound implications for development, differentiation, evolution and disease.

描述（由申请人提供）：为了确保适当的剂量补偿，雌性细胞在称为X染色体失活（XCI）的过程中选择性地使其两条X染色体中的一条失活，这是一种表观遗传调节形式。在早期雌性小鼠胚胎中，内细胞团的体细胞以相等的概率与父方或母方的X染色体重叠。因此，雌性体细胞组织中的细胞显示随机XCI模式。 乳腺是研究控制细胞特化、增殖、分化、存活和死亡的遗传途径的主要对象。泛素蛋白酶体系统（UPS）是细胞生存和死亡的关键调节因子。特别地，RING指泛素连接酶作为细胞死亡信号级联的关键组分。这些酶的细胞存活/死亡功能通常依赖于它们的RING指依赖性泛素连接酶活性 以及它们的细胞定位我们已经产生了一个条件KO小鼠模型的环指泛素连接酶RLIM，这是由X-连锁基因Rnf 12编码。我们的初步结果表明，敲除（KO）的Rnf 12在女性乳腺抑制肺泡分化和牛奶生产后怀孕。我们发现缺乏RLIM的肺泡细胞在与乳腺上皮细胞分化时会发生细胞凋亡。我们的研究结果进一步表明，这些功能主要是由父亲的Rnf 12等位基因介导的，由于非随机XCI在乳腺上皮细胞，主要沉默他们的母亲X染色体。 我们假设1）RLIM在肺泡细胞存活途径中起关键作用，并且是触发退化的关键，以及2）父方X染色体对乳腺生物学的性别特异性表观遗传调节。拟议的项目将测试这些假设，并确定三个具体目标的潜在分子机制。目的1将建立RLIM作为触发断奶诱导的肺泡细胞死亡/退化，并测试UPS系统的参与。目的2将RLIM的存活功能与核质穿梭联系起来，而目的3建立并检查了在乳腺前体细胞中建立非随机XCI模式的机制。 结合我们的研究结果将建立RLIM作为一种新的范式在调节肺泡细胞生存/死亡途径。此外，我们的研究结果将表明，乳腺生物学是决定性的性别特异性表观遗传机制与发育，分化，进化和疾病的深远影响。