DNA Replication in Thermophilic Microorganisms
Sonoko Ishino and Yoshizumi Ishino
from: Thermophilic Microorganisms (Edited by: Fu-Li Li). Caister Academic Press, U.K. (2015) Pages: 189-216.
DNA replication is essential for maintaining genetic information and transferring it from ancestor to descendant. To protect the genetic information from mutations, biological organisms have acquired several types of DNA repair systems. The extreme thermophiles living on the earth are microorganisms from the Bacteria and Archaea domains. The structures of the bacterial and archaeal genomes are circular, and the mechanism of replication initiation, by the binding of the initiator protein to the replication origin (oriC), is conserved in the two domains. The elongation process is also conserved, because similar primase, helicase, polymerase, and ligase functions are observed in the two domains. However, the proteins involved in the DNA replication process are quite different between Bacteria and Archaea, and their replication machineries seem to have evolved independently. The DNA repair system in extreme thermophiles should work efficiently to maintain their genome integrity at high temperatures. However, the DNA repair systems are diverse and still not comprehensively understood yet, although research in this field has been actively pursued in the systems from Escherichia coli to human. In this chapter, we focus on DNA replication in the thermophilic bacteria and archaea, and summarize the current understanding of the molecular mechanisms of replication in thermophilic microorganisms read more ...