Phage G4 origin of complementary DNA strand synthesis (oric) consists of three stable stem-loop structures (I, II, and III). Mutant oric sequences with alterations in the structure of stem-loop II, stem-loop III, and the stem-loop II-III spacer region have been constructed and cloned into the filamentous phage vectors to assay their functional activity. Changes in the lowermost GC base pair in the stem of stem-loop III, in the 9-bp spacer region between the stems of stem-loops II and III, and in the loop of stem-loop II, impair or abolish in vivo oric function. The results suggest that recognition sequences for dnaG primase must be present in the loop of stem-loop II, and in the spacer region between the stems of stem-loops II and III.
Bibliographical noteFunding Information:
We thank Dr. N. Nomura for providingu s with bacteriaal ndp hages trains,a ndDr. H. Ohkawaf or providingu s with syntheticD NAs. This work was fundedb y PublicH ealthS erviceG rant GM38292t o G.N.G.
- Bacteriophage genome replication
- M13 phage vector
- RNA primer
- cloned ori
- dnaG primase
- recombinant DNA
- stem-loop structures