The ACC Synthase Gene.

植物乙烯生物合成途径中的关键调节酶ACC合成酶被多种植物激素和环境刺激诱导的机制尚不清楚。Theologis博士的实验室使用与ACC mRNA互补的DNA序列获得的最新实验证据表明，IAA、创伤和锂离子等酶诱导剂在转录或转录后水平发挥作用。对西葫芦ACC合成酶基因的结构进行研究是为了在未来深入了解调控其表达的生化机制的细节。这一建议的具体目的是：对南瓜类ACC合成酶mRNA的基因组序列进行结构表征。为了实现这一目标，提出了以下实验。基因组文库将利用西葫芦幼苗的DNA构建到克隆载体EMBl3中。利用已分离的南瓜cDNA克隆pACC1为探针，通过空斑筛选杂交技术分离ACC合成酶的基因组序列。将详细研究该基因(S)的组织和结构分析。%乙烯是最简单的具有生物活性的有机分子之一。它被认为是果实成熟的激素，已知调节植物生长、发育和衰老的许多方面。ACC合成酶是乙烯合成途径中的关键酶。

The mechanism of induction of ACC synthase, the key regulatory enzyme in the ethylene biosynthetic pathway in plants, by various plant hormones and environmental stimuli is poorly understood. Recent experimental evidence obtained by Dr. Theologis' laboratory using DNA sequences complementary to the ACC mRNA indicates that enzyme inducers such as IAA, wounding and Li ions act at the transcriptional or post-transcriptional level. Studies on the structure of the ACC synthase gene in Cucurbita are proposed herein to gain insight in the future into the details of the biochemical mechanism that regulates its expression. The specific aim of this proposal is: Structural characterization of genomic sequences to ACC synthase mRNA in Cucurbita. To achieve this goal the following experiments are proposed. Genomic libraries will be constructed into the cloning vector EMBl3 using DNA from Cucurbita pepo seedlings. The genomic sequences of the ACC synthase will be isolated by plaque filter hybridization using the already isolated Cucurbita cDNA clone pACC1 as probe. The organization and structural analysis of the gene(s) will be investigated in detail. %%% Ethylene is one of the simplest organic molecules with biological activity. It is considered to be the fruit ripening hormone and is known to regulate many aspects of plant growth, development and senescence. ACC synthase is the key enzyme in the synthetic pathway of ethylene.