DNA replication process can be roughly divided into a trigger, the DNA chain extension and the termination of DNA replication.
Copying stages include DNA replication starting double-strand unsales, synthesized by transcriptional activation steps, synthesis of RNA molecules, RNA primers. In the synthesis of the lag chain, the key step of copying the first deoxynucleotide adding the first deoxynucleotide to the primer RNA is the synthesis of the leader chain DNA, once the polymerization of the leading chain DNA begins, lag The DNA synthesis on the chain also starts, and there is a necessary step before all lead-chain begins to polymerize the RNA polymerase (not primer enzyme) to transcribe a short RNA molecule. In some DNA replication, (such as plasmid cole), the RNA molecule is fed into primers that become DNA replication. However, in most DNA replication, the RNA molecule does not have primer. Its role seems to be only separate two DNA chains, exposing certain sequences to initiate the bonding, start synthesizing the RNA primer on the leading chain template DNA, which is called transcriptional activation, in the leading chain Other proteins, such as DNAA protein of E. coli during replication. These two proteins can be combined with 4 9 bp long sequences highly conservative on DNA at the starting point, and their specific functions are unclear. It may be that the seven proteins of the DNA polymerase III complex can be combined after the starting point of the DNA replication, and the origin is installed in the replication starting point. At the beginning of DNA replication, DNA spiral enzyme first unsubilt the double-stranded DNA at the start of the replication, and the two DNA chains are separated by transcription activation, and then the single-stranded DNA binding protein is combined in the unconnected chain. superior. Preprimosome consisting of two proteins such as replica X (N protein), replica y (n "protein, I protein, DNAb protein, and DNAc protein, in single-stranded DNA binding protein The intermediates were combined with single-stranded DNA, which is a leading process. The prodrus is further raised to initiate the primer assembly into an initiator. The initiator can move on a single-stranded DNA, in DNAB Asia Under the role of the base, the DNA replication starting point is recognized. First, a group of RNA primers is catalyzed by primer enzymes on the leading chain, and then the initiator is moving in the 5 '→ 3' direction in the hysteresis chain (this is a relative movement) It may also be that the lag of the rear chain template is moved, seeing), and the synthesis of the RNA primer is used in a certain distance to the use of DNA polymerase III synthesis Okazaki fragments. The function of many protein factors in the initiator is unclear. However, these components must Collaborative work can cause the initiator to move on the lag chain, identify the appropriate primer synthesis position, and polylate the nucleotide in the initial position to be an RNA primer. Since the moving direction of the initiator is in the direction of the synthetic primer on the moving direction of the lag back chain panel Therefore, the RNA primers synthesized on the lag chain are very short, generally only 3-5 nucleotides long. Moreover, these primers in the same biomass cell have similar sequences, indicating that the primer enzyme is in the DNA lag The RNA primer can be synthesized on a specific location (sequence) on the template.
