ANALYSIS OF CHROMATIN REMODELING IN MAMMARY GLAND DEVELOPMENT USING TILING ARRAYS

描述（申请人提供）：染色质结构和转录调控因子之间的相互作用在整个发育和分化过程中对基因调控具有重要作用。由于乳腺主要是在出生后发育，青春期和妊娠期的激素对其组织特异性基因表达有严格的调控，因此它是研究染色质重塑调节发育过程机制的一个很好的模型系统。本研究的长期目标是确定染色质重塑在乳腺成熟和泌乳调节中的作用，并确定基因组中在这些过程中作为调节元件的相关区域。许多研究已经确定了在发育过程中参与乳腺特异性基因转录调控的因素。然而，这些基因在染色质构象（表观遗传）水平上的全局调控机制，以确定腺体的发育和分化，却很少受到关注。我们假设染色质重塑发生在乳腺发育和分化过程中，并且是组织特异性表达模式调控的一个组成部分，该表达模式传递了腺体成熟所需的细胞记忆。ChIP- ChIP是一种结合了染色质免疫沉淀（ChIP）和高通量寡核苷酸平片阵列（ChIP）的新技术，它的发展使解决这一问题的全球方法成为可能。我们将使用ChIP-chip在小鼠的非乳腺、非定位和哺乳期乳腺组织中建立组蛋白修饰（Aim 1a）和rna聚合酶ii （Aim 1b）的组织和发育阶段特异性模式。由于乳蛋白基因在功能分化的乳腺上皮细胞中表达，我们的研究将集中在包含这些基因和其他发育调节基因的基因组结构域上。这些研究将带来对调节乳腺发育和哺乳的因素和途径的新认识，为操纵这些过程开辟新的领域，以造福母亲和儿童。此外，它们将为理解决定特定组织分化和器官发生的表观遗传变化提供基础。

DESCRIPTION (provided by applicant): The interplay between chromatin structure and transcriptional regulators has an important role in gene regulation throughout development and differentiation. Because the mammary gland develops mostly postnatally and the hormones of puberty and pregnancy tightly regulate its tissue specific gene expression, it makes an excellent model system to study the mechanisms by which chromatin remodeling regulates developmental processes in general. The long-term goal of this research is to determine the role chromatin remodeling plays in the maturation of the mammary gland and regulation of lactation, and identify the pertinent regions in the genome that function as regulatory elements in these processes. Numerous studies have identified the factors involved in transcriptional regulation of mammary specific genes during development. However, the mechanisms by which these genes are regulated globally, at the level of chromatin conformation (epigenetically), to define development and differentiation of the gland have received much less attention. We hypothesize that chromatin remodeling occurs in the mammary gland during development and differentiation, and is an integral part of the regulation of the tissue-specific expression patterns that convey the cellular memory needed for the gland's maturation. A global approach to this problem is now possible with the recent development of ChIP-chip, a new technology combining Chromatin Immuno-precipitation (ChIP) and high-throughput oligonucleotide-tiling arrays (chip). We will use ChIP-chip to establish tissue- and developmental stage-specific patterns of histone modifications (Aim 1a) and RNA-polymerase-II (Aim 1b), in non-mammary, non-locating and lactating mammary gland tissue of the mouse. As milk protein genes are expressed in functionally differentiated mammary epithelial cells, our studies will focus on the genomic domains encompassing these genes, and other developmentally regulated genes. These studies will bring about new knowledge of the factors and pathways regulating mammary gland development and lactation, opening new frontiers in the manipulation of these processes to benefit mother and child. In addition, they will provide a foundation for understanding epigenetic changes that determine differentiation and organogenesis of specific tissues. Public Health Relevance Statement: Milk is the primary source of nutrition for neonates it provides all the essential components for healthy growth and development of newborns of all mammalian species. However, our knowledge of the factors involved in establishing and maintaining lactation is far from complete. In particular the role DNA packaging plays is not well established. In this study we will investigate the DNA packaging in the developing mammary gland at a genome wide scale. These studies will provide a foundation for understanding the mechanisms that determine differentiation and organogenesis of specific tissues.