Genetics / Chemistry of the Gene / Synthesis, Modification and Repair of DNA
RNA primers in DNA replication
Fig. 26.12. Discontinuous DNA replication using RNA primers; at 5' ends of segments
No DNA polymerase enzyme is known, which can initiate synthesis of DNA chain without the availability of a primer strand. Therefore, short segments of RNA are first synthesized before actual DNA replication starts. These RNA segments are later excised and filled with DNA with the help of enzyme DNA polymerase I. It was found that if RNA synthesis is shopped by a drug
rifampicin, DNA replication stops thus proving the role of RNA primers in DNA replication (Fig. 26.12). There are several other evidences which established this point.
Fig. 26.12. Discontinuous DNA replication using RNA primers; at 5' ends of segments
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