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.

中文翻译：

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用于微调基因表达的乳脂乳球菌组成型启动子组的表征

乳脂乳球菌（同型异名：乳酸乳球菌）作为活疫苗输送的重要载体而受到越来越多的关注。如果不开发乳脂乳杆菌基因操作工具就很难实现这一目标，而对乳脂乳脂内源启动子研究的缺乏引起了我们的注意。在这里，我们报告了从L. cremoris subsp.中鉴定出的 29 个候选启动子的发现和表征。通过 RNA 测序分析cremoris NZ9000。此外，通过RT-qPCR从这29个候选启动子中筛选出18个可能的组成型启动子。然后，这 18 个启动子被克隆并通过编码 β-葡萄糖醛酸酶的报告基因gusA进行表征。最终获得了8个乳脂乳杆菌内源组成型启动子，可应用于乳酸菌的遗传操作。