BASIS OF HOXA7 REGULATION OF EPIDERMAL TRANSGLUTAMINASE

HOXA7 表皮谷氨酰胺转氨酶调节的基础

• 批准号: 2769697
• 负责人: PETER T LA CELLE
• 金额: $ 7.95万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2769697
• 关键词: DNA binding protein; cell differentiation; gel mobility shift assay; gene induction /repression; genetic enhancer element; genetic promoter element; genetic regulation; genetic regulatory element; homeobox genes; keratinocyte; polymerase chain reaction; protein glutamine gamma glutamyltransferase; tissue /cell culture; transcription factor; transfection

DESCRIPTION (from the application): The ability to control proliferation and differentiation of epidermal keratinocytes is a major obstacle in wound healing following trauma or surgery in the treatment of diseases involving abnormal epidermal differentiation, from carcinomas to psoriasis. The long range goal of this research is to identify the mechanisms underlying the genetic regulatory pathways that specify the repertoire of proteins and the associated morphology characteristic of particular stages of keratinocyte differentiation. To do this, we must identify the trans-acting factors and cis-acting elements that regulate differentiation-specific epidermal genes, such as transglutaminase type 1 (TGM 1). The highly conserved homeobox (Hox) family of transcription factors can control cell identity and differentiation, and aberrant regulation can lead deformity or to disease. Many Hox proteins recognize a common DNA sequence mainly via a small number of contacts, suggesting that additional mechanisms must underlie their diverse target specificity. It is now known that cooperative Hox interaction with cofactors can increase DNA specificity and affinity. We have identified the HOXA7 cDNA in a differentiating keratinocyte library through specific interaction with the KD-enhancer that confers keratinocyte-specific activation to E6/E7 HPV-16 promoter. Sequence homology indicates that the KD-enhancer is present in the TGM1 5' promoter region (K3), which contains a Hox DNA recognition core element as well as a 90% identical binding site for heterodimers of Hox and Pbx, the mammalian homolog of the Drosophila extradenticle. By transient transfection, HOXA7 suppresses transcriptional activity of K3 in neonatal keratinocytes, but strongly transactivates K3 in the epidermoid carcinoma cell line ME 180. We propose that HOXA7 differentially regulates the keratinocyte differentiation marker gone TGM1 in neonatal keratinocytes and ME180, through interaction with co-factors allowing cell-specific suppression or activation of the same gone. We will test this hypothesis by 1) determining the cis-acting elements in the TGM1 upstream regulatory region (K3) important in HOXA7 transactivation in neonatal keratinocytes and ME180 in vivo, and in HOXA7 binding in vitro; 2) identifying the functional domains of HOXA7 necessary for activation or repression of TGM1 in the two cell types in vivo, and for K3 binding in vitro; and 3) characterizing nuclear cofactors isolated from complexes with HOXA7 and K3. This study will elucidate the molecular mechanisms involved in HOX regulation of keratinocyte proliferation and differentiation, and in the long term may lead to new methods for controlling keratinocyte growth in re-epithelialization of wounds, and in hyperproliferative diseases.

描述（来自应用程序）： 控制表皮增殖和分化的能力 角质形成细胞是创伤后伤口愈合的主要障碍 手术在涉及异常表皮的疾病治疗中 从癌到牛皮癣的分化。 远距离目标 研究是确定遗传调节的基础机制 指定蛋白质曲目和相关的途径 角质形成细胞特定阶段的形态特征 分化。 为此，我们必须确定跨性别因素和 调节分化特异性表皮基因的顺式作用元件， 例如转谷氨酰胺酶类型1（TGM 1）。 高度保守的同源 （HOX）转录因子家族可以控制细胞身份，并且 分化和异常调节会导致畸形或疾病。 许多HOX蛋白主要通过少量识别常见的DNA序列 联系人，表明其他机制必须是他们的基础 各种目标特异性。 现在众所周知，合作霍克斯 与辅因子的相互作用可以增加DNA的特异性和亲和力。 我们 在分化的角质形成库中鉴定了Hoxa7 cDNA 通过与KD-Enhancer的特定互动 角质形成细胞特异性激活E6/E7 HPV-16启动子。 顺序 同源性表明KD-Enhancer存在于TGM1 5'启动子中 区域（K3），其中包含HOX DNA识别核心元素以及一个 HOX和PBX异二聚体的90％相同的结合位点，哺乳动物 果蝇内部的同源物。 通过瞬态转染，Hoxa7 抑制K3在新生儿角质形成细胞中的转录活性，但 在表皮癌细胞系ME中强烈反复激活K3 180。 提出HOXA7差异调节角质形成细胞分化 通过互动，标记在新生儿角质形成细胞和ME180中消失了TGM1 辅助因素允许细胞特异性抑制或激活相同 走了。 我们将通过1）确定顺式作用来检验该假设 TGM1上游监管区域（K3）中重要的元素在HOXA7中很重要 新生儿角质形成细胞和ME180在体内的反式激活，以及Hoxa7 体外结合； 2）确定需要HOXA7的功能域 用于在体内两种细胞类型中的TGM1激活或抑制，用于 K3在体外结合； 3）表征从 Hoxa7和K3的复合物。 这项研究将阐明分子 HOX调节角质形成细胞增殖和 从长远来看，差异化可能会导致新方法 控制伤口重新上皮化的角质形成细胞的生长，并在 高增殖性疾病。