| Title: | Quantitative transcript analysis of the inducible expression system pSIP: comparison of the overexpression of Lactobacillus spp. beta-galactosidases in Lactobacillus plantarum |
| Author(s): | Nguyen TT; Nguyen TH; Maischberger T; Schmelzer P; Mathiesen G; Eijsink VG; Haltrich D; Peterbauer CK; |
| Address: | "Food Biotechnology Lab, Department of Food Sciences and Technology, University of Natural Resources and Life Sciences Vienna, Austria" |
| ISSN/ISBN: | 1475-2859 (Electronic) 1475-2859 (Linking) |
| Abstract: | "BACKGROUND: Two sets of overlapping genes, lacLMReu and lacLMAci, encoding heterodimeric beta-galactosidases from Lactobacillus reuteri and Lactobacillus acidophilus, respectively, have previously been cloned and expressed using the pSIP vector system and Lactobacillus plantarum WCSF1 as host. Despite the high similarity between these lacLM genes and the use of identical cloning and expression strategies, strains harboring lacLMReu produced about twenty-fold more beta-galactosidase than strains containing lacLMAci. RESULTS: In this study, the plasmid copy numbers (PCN) of expression vectors pEH9R (lacLMReu) and pEH9A (lacLMAci) as well as the transcription levels of both lacLM genes were compared using quantitative PCR methods. Analyses of parallel fermentations of L. plantarum harboring either pEH9R or pEH9A showed that the expression plasmids were present in similar copy numbers. However, transcript levels of lacLM from L. reuteri (pEH9R) were up to 18 times higher than those of lacLM from L. acidophilus (pEH9A). As a control, it was shown that the expression levels of regulatory genes involved in pheromone-induced promoter activation were similar in both strains. CONCLUSION: The use of identical expression strategies for highly similar genes led to very different mRNA levels. The data indicate that this difference is primarily caused by translational effects that are likely to affect both mRNA synthesis rates and mRNA stability. These translational effects thus seem to be a dominant determinant for the success of gene expression efforts in lactobacilli" |
| Keywords: | "Fermentation Gene Dosage *Gene Expression Regulation, Bacterial Genetic Vectors Lactobacillus acidophilus/*enzymology Lactobacillus plantarum/*metabolism Limosilactobacillus reuteri/*enzymology Pheromones/pharmacology Plasmids/chemistry/metabolism Promote;" |
| Notes: | "MedlineNguyen, Tien-Thanh Nguyen, Thu-Ha Maischberger, Thomas Schmelzer, Philipp Mathiesen, Geir Eijsink, Vincent Gh Haltrich, Dietmar Peterbauer, Clemens K eng Comparative Study Research Support, Non-U.S. Gov't England 2011/06/24 Microb Cell Fact. 2011 Jun 22; 10:46. doi: 10.1186/1475-2859-10-46" |
