Morphogenesis of bacteriophage phi 29 of Bacillus subtilis: oriented and quantized in vitro packaging of DNA protein gp3.
The assembly of phage phi 29 occurs by a single pathway, and the DNA protein (DNA-gp3) of "packaging intermediates" can be obtained after DNase I interruption of in vitro complementation. A broad spectrum of DNA molecules of variable length was isolated from DNase I-treated proheads. Restriction endonuclease EcoRI digestion and electrophoretic analysis of these DNA molecules suggested that DNA-gp3 packaging was oriented with respect to the physical map and was a complex process. Proteinase K-treated exogenous DNA was not packaged. When exogenous DNA-gp3 was predigested with the restriction endonucleases BstEII. EcoRI, HpaI, and HpaII, the left-end fragments, ranging in size from 8 to 0.9 megadaltons, were selectively and efficiently packaged. During in vivo and in vitro assembly, DNA-gp3 is packaged into proheads, the "core-scaffolding" protein gp7 exits from the particles, and the DNA-filled heads assume the angular morphology of phage phi 29. The packaging of a 4.1-megadalton DNA-gp3 left-end fragment (one third of the genome) resulted in the exit of gp7 and the transition to angularity.
D001412:Bacillus subtilis; D001435:Bacteriophages / Q000254:growth & development / Q000378:metabolism*; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000378:metabolism*; D015246:Deoxyribonuclease EcoRI; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; D019286:Endopeptidase K; D010450:Endopeptidases; D014764:Viral Proteins / Q000378:metabolism*
D004279:DNA, Viral; D014764:Viral Proteins; D004262:DNA Restriction Enzymes; D015246:Deoxyribonuclease EcoRI; D019003:Deoxyribonuclease HpaII; C024406:endodeoxyribonuclease HpaI; D015252:Deoxyribonucleases, Type II Site-Specific; D010450:Endopeptidases; D019286:Endopeptidase K