INDUCIBLE ERYTHROMYCIN RESISTANCE

建议的研究是在《基因调控》研究的一般领域。 红霉素特异性高效诱导的模型系统 对自身和其他大环内酯类、林可酰胺类和 链球菌素B(MLS)抗生素。诱导型23S的合成 导致MLS抗性的核糖体RNA甲基酶控制在 由其构象调节的衰减器的翻译水平 通过确定核糖体装载部位的可用性来表达 抗性甲基酶的翻译启动。其中一个主要的 这项工作中尚未回答的问题是：是什么机制解释了 不同子集的诱导效率明显差异很大 不同细菌中的MLS抗生素，尽管表面上是相同的 这些抗生素作为抑制剂的效果如何？的长期目标是 这项建议是为了研究和测试基因表达调控的模型。 侧重于指定抗生素耐药性的基因；特定的 这项建议的目的是研究诱导MLS抗性的调节。 模型系统：(2)确定体内诱导的特异性 将化学合成的模型前导序列插入到表达中 为这项工作构建的载体，(2)确定氨基酸序列或 涉及前导肽和SHOW的突变体的密码子使用变化 可能与诱导相关的特异性改变，以及(3)研究 新菌株的诱导专一性和衰减器功能。 这些关于归纳的研究为理解快速反应提供了一个模型 短病程后本构MLS电阻的发展 在临床环境中使用MLS抗生素治疗。感应式最小二乘法 产生MLS抗生素的链霉菌也具有抗药性 在某些情况下，在细胞进入之前不会表现出抗性 抗生素生产。我们的工作假设是，在自然界中，领导者 多肽用于优化抗生素生产和生产之间的偶联 产生抵抗力，或者更广泛地说，在诱导性刺激之间 并增加了特定基因的表达。中将使用的方法 这些研究包括应用重组DNA技术和DNA测序 克隆化学方法合成的模型DNA衰减器序列， 分析来自自然资源的新的控制序列。

The research proposed is in the general area of gene regulation studied in a model system in which erythromycin specifically and efficiently induces resistance to itself and other macrolides, to the lincosamides, and to the streptogramin B (MLS) antibiotics. Synthesis of the inducible 23S ribosomal RNA methylase responsible for MLS resistance is controlled at the translational level by an attenuator whose conformation regulates expression by determining availability of the ribosome loading site for translation initiation of the resistance methylase. One of the main unanswered questions in this work is: What mechanism accounts for the apparent wide variability of induction efficiency of different subsets of MLS antibiotics in different bacteria despite the apparently equal efficiency of these antibiotics as inhibitors? The long term objective of this proposal is to study and test models of regulation of gene expression with emphasis on genes that specify antibiotic resistance; The specific aims of this proposal are to study regulation of inducible MLS resistance model systems by: (2) determining induction specificity in vivo following insertion of chemically synthesized model leader sequences into expression vectors constructed for this work, (2) determining amino acid sequence or codon usage alterations in mutants that involve the leader peptide and show possible associated altered specificity of induction, and (3) studying induction specificity and attenuator function in new bacterial strains. These studies of induction provide a model for understanding rapid development of constitutive MLS resistance following a short course of treatment with MLS antibiotics in a clinical setting. Inducible MLS resistance is also found in Streptomyces that produce MLS antibiotics and in some instances resistance is not expressed before the cells enter antibiotic production. It is our working hypothesis that in nature, leader peptides serve to optimize the coupling between antibiotic production and development of resistance, or more generally, between inductive stimulus and increased expression of specific genes. Methods that will be used in these studies include recombinant DNA technology and DNA sequencing applied to cloning model DNA attenuator sequences synthesized by chemical means and analyzing new control sequences from natural resources.