Expression profiling analysis of lung, heart and bone of AGA002 mutant mice

Col1a1 is located on mouse distal chromosome 11 (Celera 94607393-94622990bp; 15kb) and encodes type I procollagen that associates stoichiometrically with col1a2 in forming secreted type I mature collagen that self-assembles into a supramolecular fibrillar structure consisting of a protein family. Type I collagens are predominantly enriched in bone, cartilage, skin, tendons, and eye (i.e. in major fibrous tissues) making up the main extracellular matrix (ECM) component for support and scaffolding purposes. Col1a1 is known to be expressed in the embryo (E9.5; Northern dot blot), perioptic mesenchyme (E11), cornea (E11), skeleton (E14.5), brain meninges (E14.5), and cartilage (E14.5) at relatively early stages. Most evidence of type I collagen function is coupled to the latter stages of skeletal development, thus bypassing the major events of axis formation, tissue differentiation, and mesenchlymal-epithial interactions, for example, that are more symbolic of morphogens and growth factors. Members of the integrin cell surface receptor family of molecules mediate cell adhesion to ECM proteins such as collagen (mainly to type IV basement membrane collagen that forms into a polygonal meshwork), fibronectin, and laminin implicated in wound healing and inflammatory responses (e.g. Crohn disease, ulcerative colitis) in connective tissues. There is some evidence for protein-protein interactions between leukocyte-associated integrins and the interstitial matrix in promoting the migration and/or activation of extravasated leukocytes (e.g., T cells and monocytes) within the perivascular compartment, an ECM-rich environment. This region is surmised to be an important location where certain human leukocytes undergo differentiation (e.g. monocytes) and activation (neutrophils, monocytes, lymphocytes) upon extravascular migration. The von Willebrand factor (vWF), type C motif is found in various plasma proteins like complement factors, the integrins, collagen types, and other extracellular proteins. Thus, the majority of vWF-containing proteins are extracellular and a common feature appears to be involvement in multi protein complexes participating in numerous biological events (e.g. cell adhesion, migration, homing, pattern formation, and signal transduction). Three organs (lung, heart and bone) of 5 AGA002 mutant mice (age 2x 10 days and 3x 11 days) were analysed by cDNA microarray technology. As reference five mice, 11 days old were used 50% of the chip hybridisations are dye swap experiments.Col1a1定位于小鼠11号染色体远端区域（Celera数据库坐标94607393-94622990 bp；片段长度15 kb），编码I型前胶原。该前胶原可与Col1a2按化学计量比结合，形成分泌型I型成熟胶原，后者可自组装为以蛋白质家族为基础的超分子纤维结构。I型胶原主要富集于骨、软骨、皮肤、肌腱及眼部等主要纤维组织中，是构成细胞外基质（extracellular matrix, ECM）的核心组分，发挥支撑与支架功能。已知Col1a1在胚胎发育早期阶段即有表达，具体包括胚胎期9.5天（E9.5；Northern斑点杂交（Northern dot blot）检测）、眼周间充质（E11）、角膜（E11）、骨骼（E14.5）、脑脑膜（E14.5）及软骨（E14.5）。目前针对I型胶原功能的多数研究证据均聚焦于骨骼发育的后期阶段，因此绕过了轴形成、组织分化及间充质-上皮相互作用等更具形态发生素与生长因子特征的核心生物学事件。整合素细胞表面受体（integrin cell surface receptor）家族成员可介导细胞黏附于细胞外基质蛋白，如胶原（主要结合形成多边形网状结构的IV型基底膜胶原）、纤连蛋白（fibronectin）及层粘连蛋白（laminin）；这类蛋白与结缔组织的伤口愈合及炎症反应（如克罗恩病（Crohn disease）、溃疡性结肠炎（ulcerative colitis））密切相关。有研究证实，白细胞相关整合素与间质基质之间存在蛋白质相互作用，可促进血管外间隙（富含细胞外基质的微环境）中渗出的白细胞（如T细胞与单核细胞）的迁移及/或活化。据推测，该区域是特定人类白细胞在血管外迁移后发生分化（如单核细胞）与活化（中性粒细胞、单核细胞、淋巴细胞）的关键位点。血管性血友病因子（von Willebrand factor, vWF）的C型结构域广泛存在于多种血浆蛋白中，包括补体因子、整合素、各类胶原及其他细胞外蛋白。由此可见，多数含vWF的蛋白均为细胞外蛋白，其共同特征为参与构成多种生物学过程的多蛋白复合物，涵盖细胞黏附、迁移、归巢、模式形成及信号转导等环节。研究人员采用cDNA微阵列（cDNA microarray）技术，对5只AGA002突变小鼠的3种器官（肺、心脏与骨）进行了分析：其中2只小鼠为10日龄，剩余3只为11日龄；实验以5只11日龄的野生型小鼠作为对照，且50%的芯片杂交实验采用了染料交换（dye swap）实验设计。