Participation of the bacteriophage Mu A protein and host factors in the initiation of Mu DNA synthesis in vitro.
During bacteriophage Mu transposition, strand transfer is catalyzed in the presence of phage-encoded A and B proteins and Escherichia coli HU protein, attaching Mu ends to target DNA and creating an intermediate in transposition. Bacteriophage Mu A protein, which remains tightly bound to the Mu ends in the native strand-transfer intermediate, blocked initiation of Mu DNA replication by a system of 8 host proteins (DnaB helicase, DnaC protein, DnaG primase, DNA polymerase III holoenzyme, DNA polymerase I, DNA gyrase, DNA ligase, and single-strand binding protein). This 8-protein system had all enzymatic activities to convert the deproteinized intermediate to a cointegrate; however, additional host factor(s) were required to replicate the native intermediate. While replication of the native intermediate absolutely required DnaB helicase, DnaC protein, and DNA polymerase III holoenzyme, the specific requirements were relaxed for the deproteinized intermediate. Other host factors were able to replace these specific factors. These results indicate that Mu A protein, in conjunction with additional host factor(s), acts to promote assembly of specific host replication proteins at the Mu replication fork. This process may alter the stable interaction of Mu A protein with the ends to allow initiation of Mu DNA synthesis.
Kruklitis
R
R
Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, D.C. 20007.
Nakai
H
H
D001426:Bacterial Proteins / Q000378:metabolism*; D010583:Bacteriophage mu / Q000201:enzymology / Q000254:growth & development*; D004265:DNA Helicases; D004258:DNA Polymerase III / Q000378:metabolism; D019915:DNA Primase; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism; D053488:DnaB Helicases; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D009713:Nucleotidyltransferases / Q000378:metabolism*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D019895:Transposases; D014764:Viral Proteins
D001426:Bacterial Proteins; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C071702:DnaC protein, E coli; D029968:Escherichia coli Proteins; C050938:Mu B protein, bacteriophage; D014764:Viral Proteins; D019915:DNA Primase; C074904:DNA polymerase III, alpha subunit; D009713:Nucleotidyltransferases; D012316:RNA Nucleotidyltransferases; D019895:Transposases; D004258:DNA Polymerase III; D004265:DNA Helicases; D053488:DnaB Helicases