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 My laboratory is currently interested in biological functions of actinomycetes linear and circular replicons, developing tools for Streptomyces genomics, and genetic modification of antibiotics industrial strains.
Principal Investigator: Dr. Zhong-Jun Qin, Professor. Email: qin@sibs.ac.cn
Staff: Mei-Juan Shen, Senior Technician; Li Zhong, Research Assistant; Qing-Yu Xu, Research Assistant; Fu-Jun Dang, Research Assistant
Graduate Students: A-Na Zeng; Peng Guo; Ran Zhang; Peng-Fei Xie; Tao Wang; Wei-Hua Chen; Min Zhou; Min-Jie Hu; Zhi-Qun Lu; Yun Fan; Qiu-Xiang Cheng; Zhen-Hua Chen; Xiao-Ting Lv; Zhi-Fei Zhang; Jian Chen; Ya-lan Chen
Graduated Students: Li Zhong, 2003 (PhD); Yong Yang, 2003 (PhD); Ying-Min Zhu, 2003 (PhD)
On molecular genetics of Actinomycetes, we discovered large circular plasmids from the endophytic a tinomycetes strains, detected polyketide biosynthetic genes on linear plasmids, and finally cloned and sequenced these important linear and circular plasmids.
On development of new technology, we established a new method for cloning in vivo antibiotic biosynthetic gene clusters, and constructed a superhost of Streptomyces coelicolor with deletions of its several antibiotics gene clusters.
By collaboration with Hisun pharmaceutical company, we constructed doramectin producing strains and reached the level of industrialization.
Discovery of an Autonomous-replicating Plasmid pMX1 from Myxococcus Fulvus and the Development of a Gene Cloning System in Myxococcus Xanthus
Myxobacteria are very important for their unique characteristics such as multicellular social behavior and the production of diverse and novel bioactive secondary metabolites. However, the lack of autonomous-replicating plasmids has hindered its genetic manipulations for decades. To explore the indigenous plasmids, we screened about 150 myxobacteria strains and a circular plasmid named pMX1 was discovered from Myxococcus fulvus 124B02. The plasmid is 18,634bp in length with 68.7% GC content. Twenty-three open reading frames (ORFs) were found in the plasmid, and 14 of which are completely unknown. Plasmids containing the gene named pMX1.14, which encodes a large and unknown protein, were shown to transform M. xanthus DZ1 and DK1622 at high frequencies (~105 cfu/μg DNA), suggesting the locus is responsible for autonomous replication of pMX1. Shuttle vectors were thus constructed for both M. xanthus and E. coli. The gene pilA, which is essential for pili formation and social motility in M. xanthus, was cloned into the shuttle vectors and introduced into the pilA-deficient mutant DK10410. The transformants consequently recovered the ability to form pili and the social motility. The autonomous replicating plasmid provides a new tool for genetic manipulations in Myxococcus.
Publications:
Zhang R., Zeng A., Fang P., and Qin Z. (2008) Characterization of the replication and conjugation loci of Streptomyces circular plasmids pFP11 and pFP1 and their ability to propagate in linear mode with artificially attached telomeres. Applied and Environmental Microbiology 74: 3368-3376. Zhao J, Zhong L, Shen M, Xia Z, Cheng Q, Sun X, Zhao G, Li Y, and Qin Z. (2008) Discovery of an autonomously-replicating plasmid pMF1 from Myxococcus fulvus and the development of a gene cloning system in Myxococcus Xanthus. Applied and Environmental Microbiology 74: 1980-1987. Zhao JY, Xia ZJ, Sun X, Zhong L, Jiang DM, Liu H, Wang J, Qin ZJ, Li YZ. (2008) Cloning and characterization of an rRNA methyltransferase from Sorangium cellulosum. Biochemical and Biophysical Research Communications 370: 140-144. 钟莉, 田新莉, 周敏, 王韬, 成秋香, 陈振华, 范云, 覃重军. (2008) 内生放线菌和寄主植物的抑菌活性及其关系.中国抗生素杂志 33: 528-530. 杨勇, 覃重军. (2008) 游动双孢菌线型质粒pPR2的全序列测定及分析. 微生物学报 48: 1295-1300. 代玉梅, 周敏, 覃重军. (2008) 酸性和碱性土壤新分离的放线菌中线型和环型质粒的检测. 微生物学报 48: 244-246. 田新莉, 周敏, 周世宁, 覃重军. (2008) 水稻植物内生链霉菌中线型和环型质粒的检测. 微生物通报 35: 1562-1564.
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