DISRUPTION OF THE HSLU GENE, WHICH ENCODES AN ATPASE SUBUNIT OF THE EUKARYOTIC 26S PROTEASOME HOMOLOG IN ESCHERICHIA-COLI, SUPPRESSES THE TEMPERATURE-SENSITIVE DNAA46 MUTATION

The Escherichia coli hslVU genes encode subunits of an ATP-dependent p rotease, a homolog of the eukaryotic 26S proteasome. We found that the hslU gene is required for the temperature (40 degrees C)-sensitive ph enotype of the dnaA46 mutant, while other soluble ATP-dependent protea ses, La (Lon) and Ti (Clp), were unrelated to this dnaA46 phenotype. D isruption of the hslU gene inhibited cell growth at high temperatures. These observations suggest a specific in vivo role for HslVU protease in denatured proteins. As the absence of HslU produces minicells in M 9 medium, the protease may be involved in the cell cycle regulation. ( C) 1996 Academic Press, Inc.