A primosome is a complex of seven proteins: Dna G primase, Dna B helicase, Dna C helicase assistant, Dna T, Pri A, Pri B, and Pri C. The primosome creates RNA primers on single stranded DNA during DNA replication. The primosome is utilized once on the leading strand of DNA and repeatedly, initiating each Okazaki fragment, on the lagging DNA strand.