Proteinase PrtP (EC:3.4.21.96) is a cell envelope proteinase (CEP) highly expressed in the probiotic strain Lactobacillus paracasei BL312(VSL#3) that accounts for its anti-inflammatory properties. The main aim of this work is to understand differences in CEP expression between this strain and L. paracasei BL23. Hence, differences in the regulation by amino acid sources of four proteinase related genes (prtP, prsA, prtR1 and prtR2) were determined by RT-qPCR in BL312(VSL#3) and BL23 using as a reference BL368, a BL23 derepressed mutant lacking the response regulator (RR) PrcR. BL312(VSL#3) showed greater expression of prtP (2- to 3-fold) than BL23, and prtP was highly repressed by peptone in both strains. Two other putative CEP genes, prtR1 and prtR2, showed a low expression profile. Interestingly, when the prsA-prtP promoter region from both strains, and deleted mutants, were cloned in vector pT1GR, expression of the gfp and mrfp fluorescent reporters was always repressed in BL23 (high or low peptone) and derepressed in BL368, revealing an interesting mechanism of regulation affecting specifically to this promoter. In conclusion, BL312(VSL#3) has higher expression of prtP and other CEP related genes than BL23, that could respond to a natural deregulation in this strain, possibly independent from the RR PrcR.

中文翻译：

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两个副干酪乳杆菌益生菌菌株中细胞包膜蛋白酶（CEP）表达的差异。

蛋白酶PrtP（EC：3.4.21.96）是一种在益生菌副干酪乳杆菌BL312（VSL＃3）中高表达的细胞包膜蛋白酶（CEP），具有抗炎特性。这项工作的主要目的是了解此菌株和副干酪乳杆菌BL23之间的CEP表达差异。因此，通过RT-qPCR在BL312（VSL＃3）和BL23中使用RT-qPCR确定了四个蛋白酶相关基因（prtP，prsA，prtR1和prtR2）的氨基酸来源调节差异，使用BL23作为抑制基因，抑制了突变响应调节器（RR）PrcR。BL312（VSL＃3 ）比p23和prtP显示prtP的表达高（2-3倍）两种菌株中的蛋白highly都高度抑制了蛋白。其他两个推定的CEP基因prtR1和prtR2显示低表达。有趣的是，当将两种菌株的prsA-prtP启动子区域和缺失的突变体克隆到载体pT1GR中时，gfp和mrfp荧光报告基因的表达总是在BL23（高蛋白low或低蛋白ept）中被抑制，而在BL368中则被抑制。专门影响此启动子的调节机制。总之，BL312（VSL＃3）的prtP和其他CEP相关基因的表达高于BL23，这可能对该菌株的自然失调作出反应，可能与RR PrcR无关。