Model for the initial assembly of the archaeal replisome based on recent advances in the eukaryotic DNA replication field (see [8, 9]). (a) A double hexamer of MCM (gray) is loaded on double-stranded DNA at an archaeal replication origin. (b) The two individual hexamers are held together, so that, instead of moving apart, they will pump DNA into the central cavity of the assembly. If the pumping has a defined handedness, DNA will be unwound in the centre of the double hexamer. (c) The GINS complex (orange) in conjunction with RecJdbh or GAN (blue) stabilizes an open form of the hexameric MCM and allows extrusion of one DNA strand. (d) Resealing the MCM hexamer traps the displaced strand between the outside of MCM and the GINS assembly. (e) GINS recruits DNA primase (green).