Archaeal DNA Replication Origins and Recruitment of the MCM Replicative Helicase

DNA replication is fundamental to the propagation of all life on the planet. Remarkably, given the central importance for this process, two distinct core cellular DNA replication machineries have evolved. One is found in the bacterial domain of life and the other is present in Archaea and Eukarya. The archaeal machinery represents a simplified and presumably ancestral form of the eukaryotic DNA replication apparatus. As such, archaeal replication proteins have been studied extensively as models for their eukaryal counterparts. In addition, a number of archaea have been developed as model organisms. Accordingly, there has been a considerable increase in our knowledge of how archaeal chromosomes are replicated. It has become apparent that the majority of archaeal cells replicate their genomes from multiple origins per chromosome. Thus, at both organizational and mechanistic levels, archaeal DNA replication resembles that of eukarya. In this chapter, we will describe recent advances in our understanding of the basis of archaeal origin definition and how the archaeal initiator proteins recruit the replicative helicase to origins.