XALD--ROLE OF VERY LONG CHAIN FATTY ACYL COA SYNTHETASES

XALD--极长链脂肪酰辅酶A合成酶的作用

• 批准号: 6351855
• 负责人: Paul A. WATKINS
• 金额: $ 28.34万
• 依托单位: HUGO W. MOSER RES INST KENNEDY KRIEGER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6351855
• 关键词: Saccharomyces cerevisiae; acyl coA; adrenoleukodystrophy; disease /disorder model; enzyme activity; expression cloning; fatty acid metabolism; fatty acid synthase; gene targeting; genetic mapping; human genetic material tag; laboratory mouse; long chain fatty acid; membrane transport proteins; peroxisome; phenotype; sex linked trait; transfection

X-linked adrenoleukodystrophy (XALD) is a progressive neurodegenerative disorder with two main clinical phenotypes, a rapidly fatal, childhood- onset cerebral form and a milder, slowly progressive adult-onset peripheral neuropathy. Biochemically, decreased very long-chain fatty acid (VLCFA) activation by very long-chain acyl-CoA synthetase (VLCS) in peroxisomes results in impaired VLCFA beta-oxidation and subsequent elevation of tissue VLCFA levels. ALDP, the product of the gene defective in XALD, resembles ATP-binding cassette transmembrane transporter proteins and is not a VLCS. We hypothesize that disruption of a VLCS/ALDP interaction is responsible for loss of VLCS activity, and thus XALD. We have identified a new family of proteins that includes VLCS, and have cloned six human, mouse and yeast VLCS genes and homologs. One objective of this proposal is to identify the requirements and components of the peroxisomal VLCFA activation system and to determine how this process is disrupted in XALD. A second objective is to characterize the members of this newly described protein family with respect to both XALD and VLCFA metabolism. To accomplish this, VLCFA activation will be studied in yeast and mouse model systems. The yeast VLCS (Fatlp) will be characterized and other enzymes with VLCS activity will be identified. Gene disruption strategies will be used both to elucidate the components of VLCFA activation in yeast and to create a vehicle for expression of homologous mammalian genes. The remaining mouse and human VLCSs will be cloned and their gene products characterized. The mouse model of XALD created by targeted gene disruption will then be used to investigate the effects of ALDP absence on VLCS activity, tissue expression, and subcellular distribution. Furthermore, to determine whether VLCS tissue expression could affect phenotypic expression in XALD, the various mouse and human VLCS genes will be mapped and their map positions compared to emerging chromosomal locations of candidate XALD modifier genes.

X连锁的肾上腺肿瘤营养不良（XALD）是一种进行性神经退行性疾病，具有两个主要的临床表型，一种迅速致命的儿童发作 - 大脑形式和一种更温和的，缓慢渐进的成人外周神经病。从生物化学上，过氧化物酶体中非常长链酰基辅酶A合成酶（VLC）激活非常长链脂肪酸（VLCFA），从而导致VLCFAβ-氧化氧化和随后升高组织VLCFA水平的升高。 ALDP是XALD中基因缺陷的乘积，类似于ATP结合盒式透射膜转运蛋白，不是VLC。 我们假设VLCS/ALDP相互作用的破坏是导致VLCS活性的丧失，从而导致XALD的丧失。我们已经确定了包括VLC在内的新蛋白质家族，并克隆了六个人，小鼠和酵母VLCS基因和同源物。该提案的一个目的是确定过氧化物酶体VLCFA激活系统的要求和组成部分，并确定XALD中该过程的破坏是如何中断的。第二个目标是表征有关XALD和VLCFA代谢的新蛋白质家族的成员。为此，将在酵母和小鼠模型系统中研究VLCFA激活。将表征酵母VLC（FATLP），并确定其他具有VLCS活性的酶。基因破坏策略将既可以用来阐明酵母中VLCFA激活的成分，又可以创建一种表达同源哺乳动物基因的载体。其余的小鼠和人VLCS将被克隆，其基因产物的特征。然后，由靶向基因破坏产生的XALD小鼠模型将用于研究ALDP缺失对VLCS活性，组织表达和亚细胞分布的影响。此外，为了确定VLCS组织表达是否可能影响XALD中的表型表达，将映射各种小鼠和人VLCS基因，并且与候选XALD修饰剂基因的新兴染色体位置相比，它们的MAP位置相比。