FIG. 4.
Determination of the 5′ end of the oriTTn nick site. (A) Nicked, pFD576 DNA was used as a template for DNA sequencing reactions with the primer 2F. (B) In the first four lanes, supercoiled ccc pFD576 DNA was used as a template for DNA sequencing reactions with primer 2F. In the last four lanes, a 4.5-kb fragment from SalI-digested nicked pFD576 was purified from an alkaline gel and used as a template in DNA sequencing reactions with primer 2F. The arrow indicates the terminus of the nicked DNA strand.