How Pol α-primase is targeted to replisomes to prime eukaryotic DNA replication

By Morgan L. Jones, Valentina Aria, Yasemin Baris, Joseph T. P. Yeeles. 2023

68 citations recorded by the source corpus.

Summary During eukaryotic DNA replication, Pol α-primase generates primers at replication origins to start leading-strand synthesis and every few hundred nucleotides during discontinuous lagging-strand replication. How Pol α-primase is targeted to replication forks to prime DNA synthesis is not fully understood. Here, by determining cryoelectron microscopy (cryo-EM) structures of budding yeast and human replisomes containing Pol α-primase, we reveal a conserved mechanism for the coordination of priming by the replisome. Pol α-primase binds directly to the leading edge of the CMG (CDC45-MCM-GINS) replicative helicase via a complex interaction network. The non-catalytic PRIM2/Pri2 subunit forms two interfaces with CMG that are critical for in vitro DNA replication and yeast cell growth. These interactions position the primase catalytic subunit PRIM1/Pri1 directly above the exit channel for lagging-strand template single-stranded DNA (ssDNA), revealing why priming occurs efficiently only on the lagging-strand template and elucidating a mechanism for Pol α-primase to overcome competition from RPA to initiate primer synthesis.

Subfields: Molecular Biology

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In Molecular Biology

1. Johannes C. Walter
2. Masato T. Kanemaki
3. Sachiko Muramatsu

Citations in the corpus

• In silico protein interaction screening uncovers DONSON’s role in replication initiation (2023, background): “The mechanism by which DONSON acts downstream of replication initiation is unclear, especially given recent structural data ( 48 ), which indicates that Pol a binding to CMG would be incompatible with DONSON ’ s predicted interaction with CMG.”