Identification of the host determinant of two prolate-headed phages infecting Lactococcus lactis.
A gene responsible for host determination was identified in two prolate-headed bacteriophages of the c2 species infecting strains of Lactococcus lactis. The identification of the host determinant gene was based on low DNA sequence homology in a specific open reading frame (ORF) between prolate-headed phages with different host ranges. When a host carrying this ORF from one phage on a plasmid was infected with another phage, we obtained phages with an altered host range at a frequency of 10(-6) to 10(-7). Sequencing of phage DNA originating from 10 independent single plaques confirmed that a genetic recombination had taken place at different positions between the ORF on the plasmid and the infecting phage. The adsorption of the recombinant phages to their bacterial hosts had also changed to match the phage origin of the ORF. Consequently, it is concluded that this ORF codes for the host range determinant.
Department of Genetics and Microbiology, Applied Biotechnology, Chr. Hansen A/S, DK-2970 Hørsholm, Denmark. birgitte.stuer-lauridsen@dk.chr-hansen.com
Birgitte
B
Stuer-Lauridsen
Thomas
T
Janzen
Jannie
J
Schnabl
Eric
E
Johansen
D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D001483:Base Sequence; D013294:Lactococcus lactis / Q000821:virology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
D014764:Viral Proteins