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Characterization of a Panel of Constitutive Promoters from Lactococcus cremoris for Fine-Tuning Gene Expression
Hui Wang1, Lian-Zhong Ai1, Yong-Jun Xia1
1Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Abstract:
Lactococcus cremoris (homotypic synonym: Lactococcus lactis) is receiving increasing attention as a prominent vehicle for the delivery of live vaccines. This can hardly be achieved without developing tools for the genetic manipulation of L. cremoris, and the paucity of studies on L. cremoris endogenous promoters has attracted our attention. Here, we report the discovery and characterization of 29 candidate promoters identified from L. cremoris subsp. cremoris NZ9000 by RNA sequencing analysis. Furthermore, 18 possible constitutive promoters were obtained by RT-qPCR screening from these 29 candidate promoters. Then, these 18 promoters were cloned and characterized by a reporter gene, gusA, encoding β-glucuronidase. Eventually, eight endogenous constitutive promoters of L. cremoris were obtained, which can be applied to genetic manipulation of lactic acid bacteria.
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