The Regulation of Carbon Utilization in Streptomyces

9316912 Westpheling链霉菌是革兰氏阳性土壤细菌，由于它们非常复杂的形态发育，并且由于它们作为次级代谢产物产生用于人类和动物保健的大多数抗生素，因此特别令人感兴趣。 虽然对这些细菌的分子生理学知之甚少，但很明显，碳利用的调节在形态发育和抗生素生物合成的基因表达途径中至关重要。 为了了解链霉菌中分解代谢物控制的机制，我们正在研究一个家族的基因的调控，这些基因参与几丁质的利用，几丁质是一种复杂的碳水化合物，也是土壤中碳的主要来源。 几丁质酶的合成受到葡萄糖的严格抑制，并受到几丁质的强烈诱导。 在初步工作中，我们已经建立了至少一种几丁质的调节。 在初步工作中，我们已经建立了至少一个几丁质酶基因，chi63，发生在转录起始水平的调节。 我们一直是一个系统的分析chi63的启动子区域内的突变，并使用一个转录融合的xy1E报告基因，以确定染色体突变，确定葡萄糖阻遏和几丁质诱导几丁质酶合成的途径。 我们正在定义的几丁质酶启动子，确定调控和启动子活性的元素，开始一项研究，以确定和表征的基因，以促进全球调节链霉菌中的分解代谢产物抑制。 我们希望这项工作的结果有助于了解一类重要细菌的基因调控，其中对基因表达控制的方式知之甚少。 ***

9316912 Westpheling Streptomyces are Gram-positive soil bacteria that are of special interest because of their remarkably complex morphological development and because they produce as secondary metabolites most of the antibiotics used in human and animal health care. Although little is understood about the molecular physiology of these bacteria, it is apparent that the regulation of carbon utilization is of central importance in the gene expression pathways for both morphological development and antibiotic biosynthesis. To gain an understanding of the mechanism of catabolite control in Streptomyces we are studying the regulation of a family of genes involved in the utilization of chitin, a complex carbohydrate and a major source of carbon in the soil. The synthesis of chitinase enzymes is tightly repressed by glucose and strongly induced by chitin. In preliminary work we have established that regulation for at least one of the chitin. In preliminary work we have established that regulation for at least one of the chitinase genes, chi63, occurs at the level of transcription initiation. We have been a systematic analysis of mutations within the promoter region of chi63 and used a transcriptional fusion to the xy1E reporter gene, to identify chromosomal mutations that define the pathway for glucose repression and chitin induction of chitinase synthesis. We are defining the elements of the chitinase promoters that determine regulation and promoter activity; beginning a study to identify and characterize genes that act to facilitate the global regulation of catabolite repression in Streptomyces. %%% We hope as a result of this work to contribute to the understanding of gene regulation in an important class of bacteria where relatively little is known about the way in which gene expression is controlled. ***