DNA primase is the polymerase that synthesises small RNA primers for the Okazaki fragments made during discontinuous DNA replication. DNA primase is a heterodimer of two subunits, the small subunit Pri1 (48 kDa in yeast), and the large subunit Pri2 (58 kDa in the yeast S. cerevisiae) [1]. The large subunit of DNA primase forms interactions with the small subunit and the structure implicates that it is not directly involved in catalysis, but plays roles in correctly positioning the primase/DNA complex, and in the transfer of RNA to DNA polymerase [4].

1: A single essential gene, PRI2, encodes the large subunit of DNA primase in Saccharomyces cerevisiae. Foiani M, Santocanale C, Plevani P, Lucchini G; Mol Cell Biol 1989;9:3081-3087. PMID:2528682

2: Mutations in conserved yeast DNA primase domains impair DNA replication in vivo. Francesconi S, Longhese MP, Piseri A, Santocanale C, Lucchini G, Plevani P; Proc Natl Acad Sci U S A 1991;88:3877-3881. PMID:2023935

3: DNA replication in vitro by recombinant DNA-polymerase-alpha-primase. Stadlbauer F, Brueckner A, Rehfuess C, Eckerskorn C, Lottspeich F, Forster V, Tseng BY, Nasheuer HP; Eur J Biochem 1994;222:781-793. PMID:8026492

4: Structure of the heterodimeric core primase. Lao-Sirieix SH, Nookala RK, Roversi P, Bell SD, Pellegrini L; Nat Struct Mol Biol. 2005;12:1137-1144. PMID:16273105

5: Origin and evolution of the archaeo-eukaryotic primase superfamily and related palm-domain proteins: structural insights and new members. Iyer LM, Koonin EV, Leipe DD, Aravind L; Nucleic Acids Res. 2005;33:3875-3896. PMID:16027112