Bacteriophage T4 unf (=alc) gene function is required for late replication in the presence of plasmid pR386.
AUTOR(ES)
Herman, R E
RESUMO
The bacteriophage T4 unf gene, known to be involved in the arrest of transcription from cytosine-containing DNA, is unessential except in Escherichia coli strains containing plasmid pR386. Comparative genetic and biochemical analyses of parameters of unf+ and unf- phage growth in host cells isogenic except for the presence or absence of plasmid pR386 have shown that unf gene function is required for late phage DNA synthesis in the presence of the plasmid. Shutoff of host DNA, RNA, and protein syntheses, degradation of host DNA, adsorption, injection, and early phage DNA, RNA, and protein syntheses all occurred with normal or near-normal kinetics in unf- infections, even in the presence of the plasmid. The switch from early to late protein synthesis occurred in plasmid pR386-containing cells infected with unf+ or unf- phage. However, this switchover was slow in both cases and may be slower in unf- infections than in unf+ infections. Net incorporation of [3H]thymidine terminated at about 30 min after infection of pR386-containing cells with unf- phage at 30 degrees C. Alkaline sucrose gradient studies of the intracellular pools of replicative DNA in unf-infected plasmid pR386-containing cells indicated that this DNA is not detectably nickel or cleaved at the time that DNA synthesis aborts. The addition of chloramphenicol subsequent to early enzyme synthesis prevented the arrest of DNA synthesis in plasmid-containing cells infected with unf-phage.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=254654Documentos Relacionados
- Plasmid pR386 renders Escherichia coli cells restrictive to the growth of bacteriophage T4 unf mutants.
- Molecular proof that bacteriophage T4 alc and unf genes are the same gene.
- Identification of the Bacteriophage T4 unf (= alc) Gene Product, a Protein Involved in the Shutoff of Host Transcription
- Escherichia coli dnaT gene function is required for pBR322 plasmid replication but not for R1 plasmid replication.
- Shutoff of lambda gene expression by bacteriophage T4: role of the T4 alc gene.
