ISSN:
1572-9699
Keywords:
Lactobacillus
;
plasmid vector
;
DNA replication
;
structural stability
;
segregational stability
;
chromosomal integration
;
transcription
;
promoter
;
antisense RNA
;
translation
;
codon usage
;
protein secretion
;
heterologous gene expression
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract This paper reviews the present knowledge of the structure and properties of small (〈5 kb) plasmids present inLactobacillus spp. The data show that plasmids fromLactobacillus spp., like many plasmids from other Gram-positive bacteria, display a modular organization and replicate by a mechanism of rolling circle replication. Structurally, plasmids from lactobacilli are closely related to plasmids from other Gram-positive bacteria. They contain elements (plus- and minus origin of replication, element(s) for control of plasmid replication, mobilization function) showing extensive similarity to analogous elements in plasmids from these other organisms. It is believed that lactobacilli have acquired such elements by intra- and/or intergenic transfer mechanisms. The first part of the review is concluded with a description of plasmid vectors with aLactobacillus replicon and integrative vectors, including data concerning their structural and segregational stability. In the second part of this review we describe the progress that has been made during the last few years in identifying and characterizing elements that control expression of genetic information in lactobacilli. Based on the sequence of eleven identified and twenty presumed promoters, some preliminary conclusions can be drawn regarding the structure ofLactobacillus promoters. A typicalLactobacillus promoter shows significant similarity to promoters fromE. coli andB. subtilis. An analysis of published sequences of seventy genes indicates that the region encompassing the translation start codon AUG also shows extensive similarity to that ofE. coli andB. subtilis. Codon usage ofLactobacillus genes is not random and shows interspecies as well as intraspecies heterogeneity. Interspecies differences may, in part, be explained by differences in G + C content of different lactobacilli. Differences in gene expression levels can, to a large extent, account for intraspecies differences of codon usage bias. Finally, we review the knowledge that has become available concerning protein secretion and heterologous gene expression in lactobacilli. This part is concluded with a compilation of data on the expression inLactobacillus of heterologous genes under the control of their own promoter or under control of aLactobacillus promoter.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00873020
Permalink
