Abstract: The invention relates to a plasmid vector which does not replicate in a target organism, comprising the following components:

Abstract: The present invention is a method for the isolation and characterization of C. glutamicum genes involved in amino acid biosynthesis, specifically, encoding hom, thrB, and thrC, and sequences regulating their expression. Techniques for modifying or replacing these sequences and means for facilitating further isolations and characterizations, including promoter probe vectors which are useful in screening for high efficiency and regulatable promoters and repressors, are also disclosed.A C. glutamicum genomic library was constructed by cleaving chromosomal DNA with restriction enzymes, inserting the DNA fragments into an appropriate vector, and transforming the resulting recombinant molecules (rDNA) into C. glutamicum. Amino acid biosynthetic genes hom, thrB, and thrC, encoding homoserine dehydrogenase, homoserine kinase, and threonine synthetase, respectively, were isolated by complementation of C. glutamicum auxotrophs. The hom-thrB genes were subcloned on a 3.

Abstract: A coryneform expression and secretion system for homologous and heterologous genes consisting of the host, nucleotide sequences encoding a protein of interest, signals for expression and, optionally, targeting signals which direct membrane anchoring and for secretion and processing of the expressed protein. Regulatory signals may be utilized to control the rate and extent of expression and secretion. The system may further include compounds such as ionophores for altering the membrane transport of the host. The host itself may be mutated to alter transport, for example, by decreasing the mycolic acid content of Corynebacteria species.The preferred host is a Corynebacterium although other coryneforms deficient in extracellular protease production may also be used. C. glutamicum is used as a model organism for the secretion system.