Inducible and constitutive expression using new plasmid and integrative expression vectors for Thermus sp.
OBJECTIVE
To develop molecular tools and examine inducible and constitutive gene expression in Thermus thermophilus.


RESULTS
Two plasmid promoter probe vectors and an integrative promoter probe vector were constructed using a promoterless thermostable kanamycin nucleotidyltransferase (KmR) cassette. Three expression vectors were constructed based on a constitutive promoter J17, that functions in both Thermus and Escherichia coli. An inducible expression vector was constructed using the heat-shock inducible promoter (70 to 85 degrees C) from the dnaK gene of T. flavus, and the malate dehydrogenase gene (mdh) from T. flavus was cloned and expressed in both E. coli and T. thermophilus HB27.


CONCLUSIONS
This report describes the construction and use of improved promoter probe and expression vectors for use in Thermus species. The mdh gene can be used as a high temperature (85 degrees C) reporter gene for Thermus sp. The dnaK promoter is thermo-inducible.


CONCLUSIONS
The expression vectors and molecular tools described here are significant improvements over previously reported vectors for Thermus sp. The mdh gene and the thermo-inducible dnaK promoter will facilitate high temperature studies employing Thermus species.
Kayser
K J
KJ
Gas Technology Institute, Des Plaines, IL 60018, USA. kevin.kayser@gastechnology.org
Kwak
J H
JH
Park
H S
HS
Kilbane
J J
JJ
D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors / Q000235:genetics*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D008291:Malate Dehydrogenase / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D013696:Temperature; D016963:Thermus thermophilus / Q000235:genetics*
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D008291:Malate Dehydrogenase; C063842:dnaK protein, E coli