MOLECULAR GENETICS OF HEME BIOSYNTHETIC ENZYMES

人们对血红素新陈代谢及其扰动知道得很多，却知之甚少。 产生这种必需物质的分子机制是什么 材料受到监管。我们的目标是通过以下方式描述这些机制 关于前两种酶在血红素生物合成中的表达 途径：Delta-氨基酮丙酸合成酶(ALAS)和Delta-氨基乙酰丙酸 脱水酶(ALAD)。为了这个项目，我们带来了经过验证的大鼠肝脏 大鼠肝脏ALAD-cDNA克隆及抗ALAD单抗的研制 唉，还有。确定了七个具体目标：第一，孤立和 小鼠和大鼠ALAD-cDNAs全长序列的鉴定；第二，分离 和ALAD基因组序列的描绘；第三， 验证我们的发现，ALAD基因剂量的差异解释 近交系小鼠之间ALAD酶活性的增量差异 菌株；第四，评估(A)alad-基因拷贝的遗传多态 异交和野生小鼠的数量和(B)它可能与 环境铅；第五，描述ALAD的分子性质 不典型的环境，例如，红白血病K562细胞，胎儿 肝和人突变体；第六，全长alas-cdna和 大鼠和小鼠肝脏的相应基因DNA；第七，应用 ALAS-和ALAD-探针对分子机制的剖析 在小鼠红白血病细胞中酶表达的快速流动， 在小鼠红系祖细胞中，以及在经 产生卟啉的药物。

Much is known about heme metabolism and its perturbations, little is known of the molecular mechanisms by which the production of this essential material is regulated. Our goals are to delineate such mechanisms with respect to the expression of the first two enzymes in the heme biosynthetic pathway: delta-aminolevulinate synthase (ALAS) and delta-aminolevulinate dehydrase (ALAD). To this undertaking, we bring verified rat liver ALAD-cDNA clones and monoclonal antibodies developed against rat liver ALAD and ALAS. Seven specific aims are set: first, isolation and characterization of full-length mouse and rat ALAD-cDNA; second, isolation and delineation of ALAD genomic sequences in both species; third, verification of our finding that differences in ALAD-gene dosage account for incremental differences in ALAD enzymatic activity between inbred mouse strains; fourth, assessment of (a) genetic polymorphism for ALAD-gene copy number in outcrossed and feral mice and (b) its possible relationship to environmental lead; fifth, delineation of the molecular nature of ALAD in settings where it is atypical, e.g., erythroleukemia K562 cells, fetal liver and human mutants; sixth, isolation of full-length ALAS-cDNA and corresponding gene DNA from rat and mouse liver; and seventh, application of ALAS- and ALAD-probes to the dissection of molecular mechanisms underlying rapid flux of enzyme expression in murine erythroleukemia cells, in murine erythroid progenitors, and in the livers of animals treated with porphyrinogenic agents.