A bacteriophage T4 gene which functions to inhibit Escherichia coli Lon protease.
A bacteriophage T4 gene which functions to inhibit Escherichia coli Lon protease has been identified. This pin (proteolysis inhibition) gene was selected for its ability to support plaque formation by a lambda Ots vector at 40 degrees C. Southern blot experiments indicated that this T4 gene is included within the 4.9-kilobase XbaI fragment which contains gene 49. Subcloning experiments showed that T4 gene 49.1 (designated pinA) is responsible for the ability of the Ots vector to form plaques at 40 degrees C. Deficiencies in Lon protease activity are the only changes known in E. coli that permit lambda Ots phage to form plaques efficiently at 40 degrees C. lon+ lysogens of the lambda Ots vector containing pinA permitted a lambda Ots phage to form plaques efficiently at 40 degrees C. Furthermore, these lysogens, upon comparison with similar lysogens lacking any T4 DNA, showed reduced levels of degradation of puromycyl polypeptides and of canavanyl proteins. The lon+ lysogens that contained pinA exhibited other phenotypic characteristics common to lon strains, such as filamentation and production of mucoid colonies. Levels of degradation of canavanyl proteins were essentially the same, however, in null lon lysogens which either contained or lacked pinA. We infer from these data that the T4 pinA gene functions to block Lon protease activity; pinA does not, however, appear to block the activity of proteases other than Lon that are involved in the degradation of abnormal proteins.
Skorupski
K
K
Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway 08854.
Tomaschewski
J
J
Rüger
W
W
Simon
L D
LD
D049069:ATP-Dependent Proteases; D010582:Bacteriophage lambda / Q000254:growth & development; D001483:Base Sequence; D003001:Cloning, Molecular; D003470:Culture Media; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D005814:Genes, Viral; D005822:Genetic Vectors; D006360:Heat-Shock Proteins; D008242:Lysogeny; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000494:pharmacology*; D049070:Protease La; D011691:Puromycin / Q000031:analogs & derivatives / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*; D013604:T-Phages / Q000235:genetics*; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D003470:Culture Media; D004279:DNA, Viral; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C109919:PinA protein, Enterobacteria phage T4; D011480:Protease Inhibitors; D014764:Viral Proteins; C031736:peptidyl-puromycin; D011691:Puromycin; D004262:DNA Restriction Enzymes; C025580:endodeoxyribonuclease XBAI; D015252:Deoxyribonucleases, Type II Site-Specific; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La