Transcription factor function of hairless

无毛的转录因子功能

• 批准号: 6744456
• 负责人: ANDREW ENGELHARD
• 金额: $ 8.18万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6744456
• 关键词: DNA; apoptosis; binding sites; gene expression; gene mutation; genetic promoter element; genetic transcription; hair; hair follicle; histochemistry /cytochemistry; laboratory mouse; microarray technology; polymerase chain reaction; protein structure function; transcription factor

DESCRIPTION (provided by applicant): Recently much progress has been made in the understanding of hair follicle (HF) biology. The HF is a dynamic structure whose multiple compartments undergo successive rounds of complex and highly synchronized architectural reorganization during the growth (anagen), regression (catagen) and resting (telogen) phases of the hair cycle. Several genes that are thought to play a role in the catagen stage of the normal hair cycle, including hairless (hr), the vitamin D receptor (VDR), and the retinoid X receptor alpha (RXRalpha) have been identified on the basis of mutations in these genes which cause hair loss phenotypes. In the case of hr mutations, which cause alopecia in mice and other animals and atrichia with papular lesions (APL, OMIM 209500) in humans, cellular and morphologic changes in the structure of the HF have been characterized, yet little is known about the molecular mechanisms disrupted by hr mutations. Although the function of the protein coded by the hr gene (Hr) remains unknown, several lines of evidence suggest that Hr functions as a transcription factor of the zinc finger type. 1) An Hr domain shares homology with the GATA-1 zinc finger domain, which is responsible for DNA binding. 2) A point mutation in an APL patient results in the substitution of glycine for a conserved, presumably zinc-coordinating cysteine residue at amino acid 622. 3) Hr mutations result in the complete Joss of functional hair follicles, and 4) Hr localizes to the nucleus. This proposal aims to demonstrate that Hr is, in fact, a zinc finger transcription factor by identifying a unique consensus sequence to which Hr binds and by assaying the ability of this sequence to act as a transcriptional regulator or Hairless Responsive Element (HRE). The former aim will be accomplished through random oligonucleotide selection and amplification, a procedure known as CASTing. The latter aim will be accomplished by incorporating any presumed HREs into the promoter of luciferase reporter contructs and assaying transcriptional activity of various constructs in the presence and absence of hairless. Because the hairless phenotype is associated with changes in hair follicle morphology, and one possible mechanism identified is aberrant apoptosis, downstream effectors ofhaMess function might be members of a broad group of cell cycle genes regulated in a tissue-specific manner. The assignment of a role for hairless would be a first step in examining these possibilities.

描述（由申请人提供）：近年来，对毛囊（HF）生物学的了解取得了很大进展。HF是一个动态结构，其多个隔室在毛发周期的生长期（生长期）、退行期（退行期）和休止期（休止期）经历了连续几轮复杂且高度同步的结构重组。有几个基因被认为在正常头发周期的脱落阶段发挥作用，包括无毛（hr）、维生素D受体（VDR）和类视黄醇X受体α (rxrα)，这些基因的突变导致了脱发表型。在hr突变的情况下，导致小鼠和其他动物的脱发和人类的丘疹性秃疹（APL, OMIM 209500）， HF结构的细胞和形态学变化已经被表征，但对hr突变破坏的分子机制知之甚少。虽然由hr基因编码的蛋白（hr）的功能尚不清楚，但一些证据表明hr作为锌指型的转录因子发挥作用。1) Hr结构域与负责DNA结合的GATA-1锌指结构域具有同源性。2) APL患者的点突变导致甘氨酸取代了氨基酸622上的一个保守的、可能是锌配位的半胱氨酸残基。3) Hr突变导致功能性毛囊完全丧失，4)Hr定位于细胞核。该提案旨在通过鉴定Hr结合的独特共识序列并通过分析该序列作为转录调节剂或无毛反应元件（HRE）的能力来证明Hr实际上是锌指转录因子。前一个目标将通过随机寡核苷酸选择和扩增来实现，这一过程被称为cast。后一个目标将通过将任何假定的HREs合并到荧光素酶报告结构的启动子中，并在有无无毛的情况下分析各种结构的转录活性来实现。由于无毛表型与毛囊形态的变化有关，并且一种可能的机制被确定为异常凋亡，因此haess功能的下游效应物可能是一组以组织特异性方式调节的细胞周期基因的成员。为无毛者指定一个角色将是检验这些可能性的第一步。