Crucitti P, Lázaro J M, Benes V, Salas M
Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain.
Gene. 1998 Nov 26;223(1-2):135-42. doi: 10.1016/s0378-1119(98)00167-x.
The gene 17 of the Bacillus subtilis phage phi29 is known to be involved in the viral DNA replication in vivo. In this paper, we show that the presence of protein p17 is required when phage infection occurs at a low multiplicity of infection (moi), which is probably the natural condition for infection, but is dispensable at a high moi. Gene 17 has been cloned in an Escherichia coli expression vector and protein p17 purified. A stimulatory effect of protein p17 was demonstrated under in vitro conditions required to amplify phi29 DNA, starting with a low amount of input DNA. We propose that p17, which is synthesized early after infection, is required at the very beginning of the phage amplification, conditions in which a low number of viral DNA molecules enter the host cell, possibly to recruit the limiting amount of initiation factors at the replication origins. Once the infection process is established and the other replication proteins reach optimal concentration, p17 becomes dispensable.
已知枯草芽孢杆菌噬菌体φ29的基因17参与体内病毒DNA复制。在本文中，我们表明，当噬菌体以低感染复数（moi）感染时，蛋白质p17的存在是必需的，这可能是感染的自然条件，但在高moi时则不是必需的。基因17已被克隆到大肠杆菌表达载体中，并纯化了蛋白质p17。在从少量输入DNA开始扩增φ29 DNA所需的体外条件下，证明了蛋白质p17的刺激作用。我们提出，感染后早期合成的p17在噬菌体扩增的开始阶段是必需的，在这种情况下，少量的病毒DNA分子进入宿主细胞，可能是为了在复制起点募集有限数量的起始因子。一旦感染过程确立且其他复制蛋白达到最佳浓度，p17就不再是必需的。
