Characterization of the lytic-lysogenic switch of the lactococcal bacteriophage Tuc2009.
Tuc2009 is a temperate bacteriophage of Lactococcus lactis subsp. cremoris UC509 which encodes a CI- and Cro-type lysogenic-lytic switch region. A helix-swap of the alpha3 helices of the closely related CI-type proteins from the lactococcal phages r1t and Tuc2009 revealed the crucial elements involved in DNA recognition while also pointing to conserved functional properties of phage CI proteins infecting different hosts. CI-type proteins have been shown to bind to specific sequences located in the intergenic switch region, but to date, no detailed binding studies have been performed on lactococcal Cro analogues. Experiments shown here demonstrate alternative binding sites for these two proteins of Tuc2009. CI2009 binds to three inverted repeats, two within the intergenic region and one within the cro2009 gene. This DNA-binding pattern appears to be conserved among repressors of lactococcal and streptococcal phages. The Cro2009 protein appears to bind to three direct repeats within the intergenic region causing distortion of the bound DNA.
Kenny
John G
JG
Department of Microbiology, National University of Ireland, Cork, Ireland. j.g.kenny@student.ucc.ie
Leach
Stephen
S
de la Hoz
Ana B
AB
Venema
Gerard
G
Kok
Jan
J
Fitzgerald
Gerald F
GF
Nauta
Arjen
A
Alonso
Juan C
JC
van Sinderen
Douwe
D
D004279:DNA, Viral; D015967:Gene Expression Regulation, Viral; D005812:Genes, Switch; D016679:Genome, Viral; D013294:Lactococcus lactis / Q000821:virology*; D008242:Lysogeny; D018741:Replication Origin / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017906:Siphoviridae / Q000235:genetics / Q000502:physiology*; D014764:Viral Proteins; D016662:Virus Integration
D004279:DNA, Viral; D012097:Repressor Proteins; D014764:Viral Proteins